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Sample records for dolomedes triton foil

  1. Triton

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This photo of Triton is one of a continuing series of 'observatory phase' images obtained by the Voyager spacecraft. Lines inscribed on the image at right form a reference grid used by the Imaging Science Team. The Voyager project is managed by the Jet Propulsion Laboratory for the NASA Office of Space Science and Applications.

  2. A Comparative Analysis of the Venom Gland Transcriptomes of the Fishing Spiders Dolomedes mizhoanus and Dolomedes sulfurous

    PubMed Central

    Xu, Xunxun; Wang, Hengyun; Zhang, Fang; Hu, Zhaotun; Liang, Songping; Liu, Zhonghua

    2015-01-01

    Dolomedes sulfurous and Dolomedes mizhoanus are predaceous arthropods catching and feeding on small fish. They live in the same area and have similar habits. Their venoms exhibit some similarities and differences in biochemical and electrophysiological properties. In the present work, we first performed a transcriptomic analysis by constructing the venom gland cDNA library of D. sulfurous and 127 novel putative toxin sequences were consequently identified, which were classified into eight families. This venom gland transcriptome was then compared with that of D. mizhoanus, which revealed that the putative toxins from both spider venoms might have originated from the same gene ancestors although novel toxins were evolved independently in the two spiders. The putative toxins from both spiders contain 6–12 cysteine residues forming seven cysteine patterns. As revealed by blast search, the two venoms are rich in neurotoxins targeting ion channels with pharmacological and therapeutic significance. This study provides insight into the venoms of two closely related species of spider, which will be of use for future investigations into the structure and function of their toxins. PMID:26445494

  3. A comparative study of the molecular composition and electrophysiological activity of the venoms from two fishing spiders Dolomedes mizhoanus and Dolomedes sulfurous.

    PubMed

    Li, Jiayan; Li, Dan; Zhang, Fan; Wang, Hengyun; Yu, Hai; Liu, Zhonghua; Liang, Songping

    2014-06-01

    Dolomedes mizhoanus and Dolomedes sulfurous are two venomous spiders found in the same area in southern China and are characterized by living in water plants and feeding on fish. In this study, the chemical compositions and activities of these venoms were compared. Both venoms contain hundreds of peptides as shown by off-line RP-HPLC/MALDI-TOF-MS analysis, but have a different peptide distribution, with D. mizhoanus venom containing fewer high molecular mass (7000-9000 Da) peptides (3%) than D. sulfurous venom (25.6%). Patch-clamp analyses showed that both venoms inhibited voltage-activated Na(+), K(+) and Ca(2+) channels in rat DRG neurons, however, differences in their inhibitory effects were observed. In general, D. mizhoanus venom had lower inhibitory activity than D. sulfurous venom and both venoms had a different inhibitory spectrum against these ion channels, showing that both venoms are useful for identifying antagonists to them. In addition, intrathoracic injection of both venoms caused severe neurotoxic effects in zebrafish and death at higher concentrations, respectively. Considering that both spiders belong to the same genus, live in the same area and have similar habits, elucidation of the differences between the peptide toxins from both venoms would provide new molecular insights into the evolution of spider peptides. PMID:24593962

  4. Comprehensive analysis of the venom gland transcriptome of the spider Dolomedes fimbriatus

    PubMed Central

    Kozlov, Sergey A.; Lazarev, Vassili N.; Kostryukova, Elena S.; Selezneva, Oksana V.; Ospanova, Elena A.; Alexeev, Dmitry G.; Govorun, Vadim M.; Grishin, Eugene V.

    2014-01-01

    A comprehensive transcriptome analysis of an expressed sequence tag (EST) database of the spider Dolomedes fimbriatus venom glands using single-residue distribution analysis (SRDA) identified 7,169 unique sequences. Mature chains of 163 different toxin-like polypeptides were predicted on the basis of well-established methodology. The number of protein precursors of these polypeptides was appreciably numerous than the number of mature polypeptides. A total of 451 different polypeptide precursors, translated from 795 unique nucleotide sequences, were deduced. A homology search divided the 163 mature polypeptide sequences into 16 superfamilies and 19 singletons. The number of mature toxins in a superfamily ranged from 2 to 49, whereas the diversity of the original nucleotide sequences was greater (2–261 variants). We observed a predominance of inhibitor cysteine knot toxin-like polypeptides among the cysteine-containing structures in the analyzed transcriptome bank. Uncommon spatial folds were also found. PMID:25977780

  5. Triton mosaic

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This picture of Triton is a mosaic of the highest resolution images taken by Voyager 2 on Aug. 25, 1989 from a distance of about 40,000 kilometers (24,800 miles). The mosaic is superimposed on the lower resolution mapping images taken about 2 hours earlier in order to fill in gaps between high resolution images. The smallest features that can be seen on the images are about 0.8 kilometers (0.5 miles) across. The terminator (line separating day and night) is at the top of the picture and is centered at about 30 degrees north latitude and 330 degrees longitude. These highest resolution images were targeted for the terminator region to show details of the topography by the shadows it casts. Near the center of the picture is a depression filled with smooth plains that are probably ices which were once erupted in a fluid state. The depth of the depression is about 300 meters (900 feet) and the prominent fresh impact crater on its floor is about 20 kilometers (12 miles) in diameter and about 1 kilometer (0.6 mile) deep. On the right is an elongate crater with adjacent dark deposits above it. This feature may be an explosive eruption vent formed by gaps within the ice. The linear structure on the left is probably a fracture along which fresh ice has been extruded. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

  6. Triton's Global Heat Budget.

    PubMed

    Brown, R H; Johnson, T V; Goguen, J D; Schubert, G; Ross, M N

    1991-03-22

    Internal heat flow from radioactive decay in Triton's interior along with absorbed thermal energy from Neptune total 5 to 20 percent of the insolation absorbed by Triton, thus comprising a significant fraction of Triton's surface energy balance. These additional energy inputs can raise Triton's surface temperature between approximately 0.5 and 1.5 K above that possible with absorbed sunlight alone, resulting in an increase of about a factor of approximately 1.5 to 2.5 in Triton's basal atmospheric pressure. If Triton's internal heat flow is concentrated in some areas, as is likely, local effects such as enhanced sublimation with subsequent modification of albedo could be quite large. Furthermore, indications of recent global albedo change on Triton suggest that Triton's surface temperature and pressure may not now be in steady state, further suggesting that atmospheric pressure on Triton was as much as ten times higher in the recent past. PMID:17779439

  7. Triton's global heat budget

    SciTech Connect

    Brown, R.H.; Johnson, T.V.; Goguen, J.D. ); Schubert, G. ); Ross, M.N. )

    1991-03-22

    Internal heat flow from radioactive decay in Triton's interior along with absorbed thermal energy from Neptune total 5 to 20% of the insolation absorbed by Triton, thus comprising a significant fraction of Triton's surface energy balance. These additional energy inputs can raise Triton's surface temperature between {approximately}0.5 and 1.5 K above that possible with adsorbed sunlight alone, resulting in an increase of about a factor of {approximately}1.5 to 2.5 in Triton's basal atmospheric pressure. If Triton's internal heat flow is concentrated in some areas, as is likely, local effects such as enhanced sublimation with subsequent modification of albedo could be quite large. Furthermore, indications of recent global albedo change on Triton suggest that Triton's surface temperature and pressure may not now be in steady state, further suggesting that atmospheric pressure on Triton was as much as ten times higher in the recent past.

  8. Triton's global heat budget

    NASA Technical Reports Server (NTRS)

    Brown, R. H.; Johnson, T. V.; Goguen, J. D.; Schubert, G.; Ross, M. N.

    1991-01-01

    Internal heat flow from radioactive decay in Triton's interior along with absorbed thermal energy from Neptune total 5 to 20 percent of the isolation absorbed by Triton, thus comprising a significant fraction of Triton's surface energy balance. These additional energy inputs can raise Triton's surface temperature between about 0.5 and 1.5 K above that possible with absorbed sunlight alone, resulting in an increase of about a factor of about 1.5 to 2.5 in Triton's basal atmospheric pressure. If Triton's internal heat flow is concentrated in some areas, as is likely, local effects such as enhanced sublimation with subsequent modification of albedo could be quite large. Furthermore, indications of recent global albedo change on Triton suggest that Triton's surface temperature and pressure may not now be in steady state, further suggesting that atmospheric pressure on Triton was as much as ten times higher in the recent past.

  9. Triton's global heat budget

    NASA Technical Reports Server (NTRS)

    Brown, R. H.; Johnson, T. V.; Goguen, J. D.; Schubert, Gerald; Ross, Martin N.

    1991-01-01

    Internal heat flow from radioactive decay in Triton's interior along with absorbed thermal energy from Neptune total 5 to 20 percent of the insolation absorbed by Triton, thus comprising a significant fraction of Triton's surface energy balance. These additional energy inputs can raise Triton's surface temperature between approx. 0.5 to 1.5 K above that possible with absorbed sunlight alone, resulting in a factor of approx. 1.5 to 2.5 increase in Triton's basal atmospheric pressure. If Triton's internal heatflow is concentrated in some areas, as is likely, local effects such as enhanced sublimation with subsequent modification of albedo could be quite large. Furthermore, indications of recent albedo change on Triton suggest that Triton's surface temperature and pressure may not now be in steady state, further suggesting that atmospheric pressure on Triton was as much as 10 times higher in the recent past.

  10. Foil Artists

    ERIC Educational Resources Information Center

    Szekely, George

    2010-01-01

    Foil can be shaped into almost anything--it is the all-purpose material for children's art. Foil is a unique drawing surface. It reflects, distorts and plays with light and imagery as young artists draw over it. Foil permits quick impressions of a model or object to be sketched. Foil allows artists to track their drawing moves, seeing the action…

  11. Tectonics on Triton

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1993-01-01

    Tectonic features on Triton have been mapped as part of a larger study of the geology of Triton. Few purely tectonic structures are found on Triton: some grabens and possibly some compressive ridges. However, most of the other structures seen (primarily cryovolcanic in origin) exhibit tectonic control. A regional tectonic network has the following dominant orientations: N-S, E-W, NE-SW, and NW-SE. Most of the orientations are consistent with tidal deformations related to Triton's decreasing orbital radius. Localized quasi-concentric patterns may be due to interior processes such as mantle plumes.

  12. Global Warming on Triton

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Hammel, H. B.; Wasserman, L. H.; Franz, O. G.; McDonald, S. W.; Person, M. J.; Olkin, C. B.; Dunham, E. J.; Spencer, J. R.; Stansberry, J. A.; Buie, M. W.; Pasachoff, J. M.; Babcock, B. A.; McConnochie, T. H.

    1998-01-01

    Triton, Neptune's largest moon, has been predicted to undergo significant seasonal changes that would reveal themselves as changes in its mean frost temperature. But whether this temperature should at the present time be increasing, decreasing or constant depends on a number of parameters (such as the thermal properties of the surface, and frost migration patterns) that are unknown. Here we report observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global warming since 1989. Our most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years, significantly faster than predicted by any published frost model for Triton. Our result suggests that permanent polar caps on Triton play a c dominant role in regulating seasonal atmospheric changes. Similar processes should also be active on Pluto.

  13. Water Ice on Triton

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.; Roush, Ted L.; Owen, Tobias C.; Schmitt, Bernard; Quirico, Eric; Geballe, Thomas R.; deBergh, Catherine; Bartholomew, Mary Jane; DalleOre, Cristina M.; Doute, Sylvain

    1999-01-01

    We report the spectroscopic detection of H2O ice on Triton, evidenced by the broad absorptions in the near infrared at 1.55 and 2.04 micron. The detection on Triton confirms earlier preliminary studies (D. P. Cruikshank, R. H. Brown, and R. N. Clark, Icarus 58, 293-305, 1984). The spectra support the contention that H2O ice on Triton is in a crystalline (cubic or hexagonal) phase. Our spectra (1.87-2.5 micron) taken over an interval of nearly 3.5 years do not show any significant changes that might relate to reports of changes in Triton's spectral reflectance (B. Buratti, M. D. Hicks, and R. L. Newburn, Jr., Nature 397, 219, 1999), or in Triton's volatile inventory (J. L. Elliot et al., Nature 393, 765-767, 1998).

  14. Triton's Distorted Atmosphere

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Stansberry, J. A.; Olkin, C. B.; Agner, M. A.; Davies, M. E.

    1998-01-01

    A stellar-occultation light curve for Triton shows asymmetry that can be understood if Triton's middle atmosphere is distorted from spherical symmetry. Although a globally oblate model can explain the data, the inferred atmospheric flattening is so large that it could be caused only by an unrealistic internal mass distribution or highly supersonic zonal winds. Cyclostrophic winds confined to a jet near Triton's northern or southern limbs (or both) could also be responsible for the details of the light curve, but such winds are required to be slightly supersonic. Hazes and clouds in the atmosphere are unlikely to have caused the asymmetry in the light curve.

  15. Triton: A hot potato

    NASA Technical Reports Server (NTRS)

    Kirk, R. L.; Brown, R. H.

    1991-01-01

    The effect of sunlight on the surface of Triton was studied. Widely disparate models of the active geysers observed during Voyager 2 flyby were proposed, with a solar energy source almost their only feature. Yet Triton derives more of its heat from internal sources (energy released by the radioactive decay) than any other icy satellite. The effect of this relatively large internal heat on the observable behavior of volatiles on Triton's surface is investigated. The following subject areas are covered: the Global Energy Budget; insulation polar caps; effect on frost stability; mantle convection; and cryovolcanism.

  16. Triton - Voyager's finale

    NASA Technical Reports Server (NTRS)

    Brown, R. H.

    1992-01-01

    The investigation of the Neptunian satellite Triton by the Voyager 2 is described with interpretations of the object's nature and composition. The orbit, seasonal cycle, and southern-hemisphere solstice are described, and the composition of the satellite is discussed. Triton's mass and radius are known, and the objects is made up of about 70 percent rock and organics and 30 percent ice by mass. Triton's interior is warm and geologically active considering its distance from the sun, and large amounts of frozen methane and nitrogen are theorized to contribute to the object's high reflectivity. Also noted in the Voyager color images are creeping ice, cryogenic lava, and dark streaks on the south polar cap from nitrogen gas leaks driven by a type of greenhouse effect. Triton represents a class of satellite that has not been observed previously: a moon-sized body in a retrograde inclined orbit from the class of objects that coalesced to form Neptune.

  17. The Triton torus revisited

    NASA Technical Reports Server (NTRS)

    Richardson, John D.; Eviatar, A.; Delitsky, M. L.

    1990-01-01

    Prior to the Voyager encounter with Neptune, Delitsky et al. (1989) predicted that a torus of ions emanating from Triton would be discovered. These predictions are reexamined in light of the Voyager results. Sputtering of Triton's atmosphere can produce the heavy ion densities inferred at Triton's orbit by the Voyager plasma experiment if the ion residence time is about 30 days. The torus is found to be longitudinally asymmetric near Triton, with peak densities at longitudes of 170 and 350 deg. The total nitrogen flux due to sputtering is about 2 x 10 to the 21st/s. The consequences of larger escape fluxes of both N2 and H2 are investigated; it is difficult to reconcile large escape fluxes with the plasma and ultraviolet spectrometer observations.

  18. Detail of Triton

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This color photo of Neptune's large satellite Triton was obtained on Aug. 24 1989 at a range of 530,000 kilometers (330,000 miles). The resolution is about 10 kilometers (6.2 miles), sufficient to begin to show topographic detail. The image was made from pictures taken through the green, violet and ultraviolet filters. In this technique, regions that are highly reflective in the ultraviolet appear blue in color. In reality, there is no part of Triton that would appear blue to the eye. The bright southern hemisphere of Triton, which fills most of this frame, is generally pink in tone as is the even brighter equatorial band. The darker regions north of the equator also tend to be pink or reddish in color. JPL manages the Voyager project for NASA's Office of Space Science, Washington, DC.

  19. Classroom Foils

    ERIC Educational Resources Information Center

    Pafford, William N.

    1970-01-01

    Aluminum foil, because of its characteristics, can be used for many elementary science activities: demonstrating Archimedes Principle, how to reduce cohesion, reflection and mirror effect, fuse action, condensation, friction, and as containers and barriers. (BR)

  20. Neptune's story. [Triton's orbit perturbation

    NASA Technical Reports Server (NTRS)

    Goldreich, P.; Murray, N.; Longaretti, P. Y.; Banfield, D.

    1989-01-01

    It is conjectured that Triton was captured from a heliocentric orbit as the result of a collision with what was then one of Neptune's regular satellites. The immediate post-capture orbit was highly eccentric. Dissipation due to tides raised by Neptune in Triton caused Triton's orbit to evolve to its present state in less than one billion years. For much of this time Triton was almost entirely molten. While its orbit was evolving, Triton cannibalized most of the regular satellites of Neptune and also perturbed Nereid, thus accounting for that satellite's highly eccentric and inclined orbit. The only regular satellites of Neptune that survived were those that formed well within 5 Neptune radii, and they move on inclined orbits as the result of chaotic perturbations forced by Triton.

  1. Triton torus and Neptune aurora

    NASA Technical Reports Server (NTRS)

    Cheng, Andrew F.

    1990-01-01

    Triton is shown to be the dominant source of plasma for L equal to or greater than 7 in the magnetosphere of Neptune. Triton maintains a neutral hydrogen torus of average density comparable to a greater than that of the Titan torus at Saturn. The Triton torus may be detectable in H Lyman-alpha emissions. However, the energy source from plasma outward transport and mass loading in the Triton torus is insufficient to explain the Neptune aurora. It is proposed that Neptune's aurora is driven mainly by a solar wind interaction.

  2. Triton 2 (1B)

    NASA Technical Reports Server (NTRS)

    Clark, Michelle L.; Meiss, A. G.; Neher, Jason R.; Rudolph, Richard H.

    1994-01-01

    The goal of this project was to perform a detailed design analysis on a conceptually designed preliminary flight trainer. The Triton 2 (1B) must meet the current regulations in FAR Part 23. The detailed design process included the tasks of sizing load carrying members, pulleys, bolts, rivets, and fuselage skin for the safety cage, empennage, and control systems. In addition to the regulations in FAR Part 23, the detail design had to meet established minimums for environmental operating conditions and material corrosion resistance.

  3. Triton's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This polar projection of Triton's southern hemisphere provides a view of the southern polar cap and bright equatorial fringe. The margin of the cap is scalloped and ranges in latitude from +10 degrees to -30 degrees. The bright fringe is closely associated with the cap's margin; from it, diffuse bright rays extend north-northeast for hundreds of kilometers. The bright fringe probably consists of very fresh nitrogen frost or snow, and the rays consist of bright-fringe materials that were redistributed by north-moving Coriolis-deflected winds.

  4. Geomorphology of Triton's polar materials

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1993-01-01

    One of Triton's most debated puzzles is the nature, distribution, and transport of its atmospheric volatiles. The full potential of constraints provided by detailed observations of the morphology and distribution of the polar deposits has not been realized. The objective of this study is characterization of the morphology, distribution, stratigraphy, and geologic setting of Triton's polar materials.

  5. On the origin of Triton

    NASA Astrophysics Data System (ADS)

    Celebonovic, V.

    1986-01-01

    The origin of Triton, based on the theory of materials under high pressure by Savic and Kasanin (1962, 1965), is described. The mean molecular weight (A) and the volume of one gram mole of Triton's material (V) are evaluated using its values of mass and radius; it is calculated that A = 67 + or - 2 and V = 3 + or - 2. These values are compared with Celebonovic's (1983) model of Neptune; it is observed that the mean molecular weight of Triton is ten times larger than Neptune's. The cause of this large variation in chemical composition is investigated. It is hypothesized that Triton and Neptune formed in different regions of the solar system, and that Triton was ejected from its primordial orbit and was later captured by Neptune.

  6. Triton, Pluto and Charon

    NASA Technical Reports Server (NTRS)

    Cruikshank, D. P.

    1990-01-01

    On the eve of the Voyager encounter with Neptune and Triton, the knowledge of the surface and atmosphere of the satellite has made some progress. Methane, and perhaps molecular nitrogen, appears to dominate the surface and atmospheric chemistry. Sketchy evidence suggests changes in the disposition and state of the volatile materials on this body in the past few years, perhaps in response to the extreme seasons. Pluto and its satellite Charon are at last revealed in some detail, chiefly resulting from observations of the mutual transits and occultations of 1985-1990. A stellar occultation by Pluto in 1988 has given the first detailed information on the planet's atmosphere. The density of the Pluto-Charon system indicates a bulk composition consisting of silicates and water ice, suggesting formation directly from the solar nebula.

  7. Foil bearings

    NASA Technical Reports Server (NTRS)

    Elrod, David A.

    1993-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  8. Evolution of Triton's volatile budget

    NASA Technical Reports Server (NTRS)

    Lunine, J. I.

    1993-01-01

    Triton's volatile budget provides important links to planetary formation processes in the cold outer solar nebula. However, the budget has been modified by processes subsequent to the accretion of this body. It is of interest to assess whether certain formation environments can be ruled out for Triton on the basis of its current volatile abundances, and also to quantify some of the post-accretional processes by which the abundances have been modified.

  9. Foil Electron Multiplier

    DOEpatents

    Funsten, Herbert O.; Baldonado, Juan R.; Dors, Eric E.; Harper, Ronnie W.; Skoug, Ruth M.

    2006-03-28

    An apparatus for electron multiplication by transmission that is designed with at least one foil having a front side for receiving incident particles and a back side for transmitting secondary electrons that are produced from the incident particles transiting through the foil. The foil thickness enables the incident particles to travel through the foil and continue on to an anode or to a next foil in series with the first foil. The foil, or foils, and anode are contained within a supporting structure that is attached within an evacuated enclosure. An electrical power supply is connected to the foil, or foils, and the anode to provide an electrical field gradient effective to accelerate negatively charged incident particles and the generated secondary electrons through the foil, or foils, to the anode for collection.

  10. Photometric properties of Triton hazes

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Veverka, J.

    1994-01-01

    Voyager imaging observations of Triton have been used to investigate the characteristics of the atmospheric hazes on Triton at three wavelengths: violet (0.41 micrometers), blue (0.48 micrometers), and green (0.56 micrometers). The globally averaged optical depth is wavelength dependent, varying from 0.034 in green to 0.063 in violet. These photometric results are dominated by the properties of localized discrete clouds rather than by those of the thinner, more widespread haze known to occur on Triton. The cloud particles are bright, with single-scattering albedos near unity at all three wavelengths, suggestive of a transparent icy condensate. The asymmetry parameter (+0.6) and the wavelength dependence of the optical depth both indicate cloud particles 0.2-0.4 micrometers in radius. The clouds are concentrated at 50-60 deg S latitude, where opacities up to three times the global average are observed. This is the same latitude region where most of the evidence for current surface activity is found, suggesting that the clouds may be related to the plumes or at least to some process connected with the sublimation of the south polar cap. The effects of possible temporal variations in the haze opacity are examined. Increases in the haze opacity tend to redden Triton. However, the degree of reddening is not sufficient to explain the full range of observed changed in Triton over the past decade; variations in the surface properties appear to be necessary.

  11. A control network of Triton

    NASA Technical Reports Server (NTRS)

    Davies, Merton E.; Rogers, Patricia G.; Colvin, Tim R.

    1991-01-01

    A control network for Triton has been computed using a bundle-type analytical triangulation program. The network contains 105 points that were measured on 57 Voyager-2 pictures. The adjustment contained 1010 observation equations and 382 normal equations and resulted in a standard measurement error of 13.36 microns. The coordinates of the control points, the camera orientation angles at the times when the pictures were taken, and Triton's mean radius were determined. A separate statistical analysis confirmed Triton's radius to be 1352.6 + or - 2.4 km. Attempts to tie the control network around the satellite were unsuccessful because discontinuities exist in high-resolution coverage between 66 deg and 289 deg longitude, north of 38 deg latitude, and south of 78 deg latitude.

  12. A control network of Triton

    NASA Astrophysics Data System (ADS)

    Davies, Merton E.; Rogers, Patricia G.; Colvin, Tim R.

    1991-08-01

    A control network for Triton has been computed using a bundle-type analytical triangulation program. The network contains 105 points that were measured on 57 Voyager-2 pictures. The adjustment contained 1010 observation equations and 382 normal equations and resulted in a standard measurement error of 13.36 microns. The coordinates of the control points, the camera orientation angles at the times when the pictures were taken, and Triton's mean radius were determined. A separate statistical analysis confirmed Triton's radius to be 1352.6 + or - 2.4 km. Attempts to tie the control network around the satellite were unsuccessful because discontinuities exist in high-resolution coverage between 66 deg and 289 deg longitude, north of 38 deg latitude, and south of 78 deg latitude.

  13. Foil changing apparatus

    DOEpatents

    Crist, Charles E.; Ives, Harry C.; Leifeste, Gordon T.; Miller, Robert B.

    1988-01-01

    A self-contained hermetically sealed foil changer for advancing a portion of foil web into a position normal to the path of a high energy particle beam. The path of the beam is defined generally by an aperture plate and cooperating axially movable barrel such that the barrel can be advanced toward the plate thereby positioning a portion of the foil across the beam path and sealing the foil between the barrel and the plate to form a membrane across said beam path. A spooling apparatus contained in the foil changer permits selectively advancing a fresh supply of foil across the beam path without breaking the foil changer seal.

  14. Global Color Mosaic of Triton

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Global color mosaic of Triton, taken in 1989 by Voyager 2 during its flyby of the Neptune system. Color was synthesized by combining high- resolution images taken through orange, violet, and ultraviolet filters; these images were displayed as red, green, and blue images and combined to create this color version. With a radius of 1,350 (839 mi), about 22% smaller than Earth's moon, Triton is by far the largest satellite of Neptune. It is one of only three objects in the Solar System known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn's giant moon, Titan). Triton has the coldest surface known anywhere in the Solar System (38 K, about -391 degrees Farenheit); it is so cold that most of Triton's nitrogen is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice. The pinkish deposits constitute a vast south polar cap believed to contain methane ice, which would have reacted under sunlight to form pink or red compounds. The dark streaks overlying these pink ices are believed to be an icy and perhaps carbonaceous dust deposited from huge geyser-like plumes, some of which were found to be active during the Voyager 2 flyby. The bluish-green band visible in this image extends all the way around Triton near the equator; it may consist of relatively fresh nitrogen frost deposits. The greenish areas include what is called the cataloupe terrain, whose origin is unknown, and a set of 'cryovolcanic' landscapes apparently produced by icy-cold liquids (now frozen) erupted from Triton's interior.

  15. Global Color Mosaic of Triton

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Global color mosaic of Triton, taken in 1989 by Voyager 2 during its flyby of the Neptune system. Color was synthesized by combining high-resolution images taken through orange, violet, and ultraviolet filters; these images were displayed as red, green, and blue images and combined to create this color version. With a radius of 1,350 (839 mi), about 22% smaller than Earth's moon, Triton is by far the largest satellite of Neptune. It is one of only three objects in the Solar System known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn's giant moon, Titan). Triton has the coldest surface known anywhere in the Solar System (38 K, about -391 degrees Fahrenheit); it is so cold that most of Triton's nitrogen is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice. The pinkish deposits constitute a vast south polar cap believed to contain methane ice, which would have reacted under sunlight to form pink or red compounds. The dark streaks overlying these pink ices are believed to be an icy and perhaps carbonaceous dust deposited from huge geyser-like plumes, some of which were found to be active during the Voyager 2 flyby. The bluish-green band visible in this image extends all the way around Triton near the equator; it may consist of relatively fresh nitrogen frost deposits. The greenish areas includes what is called the cantaloupe terrain, whose origin is unknown, and a set of 'cryovolcanic' landscapes apparently produced by icy-cold liquids (now frozen) erupted from Triton's interior.

  16. Color and chemistry on Triton

    NASA Technical Reports Server (NTRS)

    Thompson, W. Reid; Sagan, Carl

    1990-01-01

    The surface of Triton is very bright but shows subtle yellow to peach hues which probably arise from the production of colored organic compounds from CH4 + N2 and other simple species. In order to investigate possible relationships between chemical processes and the observed surface distribution of chromophores, the surface units are classified according to color/albedo properties, the rates of production of organic chromophores by the action of ultraviolet light and high-energy charged particles is estimated, and rates, spectral properties, and expected seasonal redistribution processes are compared to suggest possible origins of the colors seen on Triton's surface.

  17. Triton's streaks as windblown dust

    NASA Technical Reports Server (NTRS)

    Sagan, Carl; Chyba, Christopher

    1990-01-01

    Explanations for the surface streaks observed by Voyager 2 on Triton's southern hemisphere are discussed. It is shown that, despite Triton's tenuous atmosphere, low-cohesion dust trains with diameters of about 5 micron or less may be carried into suspension by aeolian surface shear stress, given expected geostrophic wind speeds of about 10 m/s. For geyser-like erupting dust plumes, it is shown that dust-settling time scales and expected wind velocities can produce streaks with length scales in good agreement with those of the streaks. Thus, both geyserlike eruptions or direct lifting by surface winds appear to be viable mechanisms for the origin of the streaks.

  18. Color and chemistry on Triton

    NASA Astrophysics Data System (ADS)

    Thompson, W. Reid; Sagan, Carl

    1990-10-01

    The surface of Triton is very bright but shows subtle yellow to peach hues which probably arise from the production of colored organic compounds from CH4 + N2 and other simple species. In order to investigate possible relationships between chemical processes and the observed surface distribution of chromophores, the surface units are classified according to color/albedo properties, the rates of production of organic chromophores by the action of ultraviolet light and high-energy charged particles is estimated, and rates, spectral properties, and expected seasonal redistribution processes are compared to suggest possible origins of the colors seen on Triton's surface.

  19. Color and Chemistry on Triton

    NASA Astrophysics Data System (ADS)

    Reid Thompson, W.; Sagan, Carl

    1990-10-01

    The surface of Triton is very bright but shows subtle yellow to peach hues which probably arise from the production of colored organic compounds from CH_4 + N_2 and other simple species. In order to investigate possible relationships between chemical processes and the observed surface distribution of chromophores, we classify the surface units according to color/albedo properties, estimate the rates of production of organic chromophores by the action of ultraviolet light and high-energy charged particles, and compare rates, spectral properties, and expected seasonal redistribution processes to suggest possible origins of the colors seen on Triton's surface.

  20. Triton College: One Institution's Search for Distinctiveness.

    ERIC Educational Resources Information Center

    Townsend, Barbara K.; Catanzaro, James L.

    1989-01-01

    Recounts Triton College's efforts to identify its distinctive elements. Reviews empirical evidence showing that Triton's school schedule, curricular offerings, and continuing education and support services are distinctive among local colleges. Discusses students' and staff members' perceptions of Triton. Considers the value of the research to the…

  1. Ices on the surface of Triton

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.; Roush, Ted L.; Owen, Tobias C.; Geballe, Thomas R.; De Bergh, Catherine; Schmitt, Bernard; Brown, Robert H.; Bartholomew, Mary J.

    1993-01-01

    The near-infrared spectrum of Triton reveals ices of nitrogen, methane, carbon monoxide, and carbon dioxide, of which nitrogen is the dominant component. Carbon dioxide ice may be spatially segregated from the other more volatile ices, covering about 10 percent of Triton's surface. The absence of ices of other hydrocarbons and nitriles challenges existing models of methane and nitrogen photochemistry on Triton.

  2. Ices on the surface of Triton

    NASA Astrophysics Data System (ADS)

    Cruikshank, D. P.; Roush, T. L.; Owen, T. C.; Geballe, T. R.; de Bergh, C.; Schmitt, B.; Brown, R. H.; Bartholomew, M. J.

    1993-08-01

    The near-infrared spectrum of Triton reveals ices of nitrogen, methane, carbon monoxide, and carbon dioxide, of which nitrogen is the dominant component. Carbon dioxide ice may be spatially segregated from the other more volatile ices, covering about 10 percent of Triton's surface. The absence of ices of other hydrocarbons and nitriles challenges existing models of methane and nitrogen photochemistry on Triton.

  3. Triton College, 1980-1982.

    ERIC Educational Resources Information Center

    Triton Coll., River Grove, IL.

    Focusing on the period from 1980 to 1982, this public information booklet reviews the accomplishments and innovative programs of Triton College. After an introduction by the college president summarizing these achievements, subsequent sections focus on: (1) training partnerships with business and industry, including cooperative agreements with the…

  4. The Humanities at Triton College.

    ERIC Educational Resources Information Center

    Jacot, Robert E.; Prendergast, Nancy E.

    Designed to assist college personnel in assessing program needs, this report provides an overview of the humanities programs at Triton College. Part I focuses on curricular humanities programs, including discussions of the role and objectives of the School of Arts and Sciences; humanities courses offered in the school; special humanities…

  5. Redesigning TRACER trial after TRITON.

    PubMed

    Serebruany, Victor L

    2015-10-15

    Designing of smart clinical trials is critical for regulatory approval and future drug utilization. Importantly, trial design should be reconsidered if the interim analyses suggest unexpected harm, or conflicting results were yielded from the other trials within the same therapeutic area. With regard to antiplatelet agents, the perfect example is redesigning of the ongoing PRoFESS trial by eliminating aspirin from clopidogrel arm after the earlier MATCH trial results became available. The goal was to aseess the unchanged TRACER trial design in light of the evidence yielded from the earlier completed TRITON trial. TRACER was designed as a triple versus dual antiplatelet trial in NSTEMI patients with no previous long-term outcome data supporting such aggressive strategy. TRITON data represented dual versus dual antiplatelet therapy, and became available before TRACER enrollment starts revealing prasugrel front-loaded early vascular benefit predominantly in STEMI patients with the growing over time bleeding and cancer risks. Moreover, large prasugrel NSTEMI TRITON cohort exhibited trend towards excess mortality in experimental arm warning against aggressive TRACER design. The long-term TRITON results in general, and especially in the NSTEMI patients challenge unchanged TRACER trial design. Applying dual, rather than triple antiplatelet therapy protocol modification should be considered in TRACER to minimize bleeding, cancer, and non-cardiovascular death risks. PMID:26126053

  6. 6Li foil thermal neutron detector

    SciTech Connect

    Ianakiev, Kiril D; Swinhoe, Martyn T; Favalli, Andrea; Chung, Kiwhan; Macarthur, Duncan W

    2010-01-01

    In this paper we report on the design of a multilayer thermal neutron detector based on {sup 6}Li reactive foil and thin film plastic scintillators. The {sup 6}Li foils have about twice the intrinsic efficiency of {sup 10}B films and about four times higher light output due to a unique combination of high energy of reaction particles, low self absorption, and low ionization density of tritons. The design configuration provides for double sided readout of the lithium foil resulting in a doubling of the efficiency relative to a classical reactive film detector and generating a pulse height distribution with a valley between neutron and gamma signals similar to {sup 3}He tubes. The tens of microns thickness of plastic scintillator limits the energy deposited by gamma rays, which provides the necessary neutron/gamma discrimination. We used MCNPX to model a multilayer Li foil detector design and compared it with the standard HLNCC-II (18 {sup 3}He tubes operated at 4 atm). The preliminary results of the {sup 6}Li configuration show higher efficiency and one third of the die-away time. These properties, combined with the very short dead time of the plastic scintillator, offer the potential of a very high performance detector.

  7. Exploring Triton with multiple landers

    NASA Technical Reports Server (NTRS)

    Balint, Tibor S.

    2005-01-01

    In our pathway for Outer Planetary Exploration several mission concepts were considered, based on the proposed JIMO mission architecture. This paper describes a JIMO follow-on mission concept to Neptunes largest moon. Triton is a target of interest for outer solar system studies. It has a highly inclined retrograde orbit, suggesting that it may have been a Kuiper Belt object captured by Neptune. Given this assumption its composition, which may include organic materials, would be of significant scientific interest.

  8. The venom of the fishing spider Dolomedes sulfurous contains various neurotoxins acting on voltage-activated ion channels in rat dorsal root ganglion neurons.

    PubMed

    Wang, Hengyun; Zhang, Fan; Li, Dan; Xu, Shiyan; He, Juan; Yu, Hai; Li, Jiayan; Liu, Zhonghua; Liang, Songping

    2013-04-01

    Dolomedes sulfurous is a venomous spider distributed in the south of China and characterized with feeding on fish. The venom exhibits great diversity and contains hundreds of peptides as revealed by off-line RP-HPLC/MALDI-TOF-MS analysis. The venom peptides followed a triple-modal distribution, with 40.7% of peptides falling in the mass range of 1000-3000 Da, 25.6% peptides in the 7000-9000 Da range and 23.5% peptides in the 3000-5000 Da range. This distribution modal is rather different from these of peptides from other spider venoms analyzed. The venom could inhibit voltage-activated Na(+), K(+) and Ca(2+) channels in rat DRG neurons as revealed by voltage-clamp analysis. Significantly, the venom exhibited inhibitory effects on TTX-R Na(+) and T-type Ca(2+) currents, suggesting that there exist both channel antagonists which might be valuable tools for investigation of both channels and drug development. Additionally, intrathoracically injection of venom could cause serve neurotoxic effects on zebrafish and death at higher concentrations. The LD50 value was calculated to be 28.8 μg/g body weight. Our results indicated that the venom of D. sulfurous contain diverse neurotoxins which serve to capture prey. Intensive studies will be necessary to investigate the structures and functions of specific peptides of the venom in the future. PMID:23391637

  9. Voyager imaging of Triton's clouds and hazes

    NASA Technical Reports Server (NTRS)

    Rages, Kathy; Pollack, James B.

    1992-01-01

    Results are presented from a detailed analysis of Voyager images of Triton obtained at the highest solar phase angles; these have been fit to Mie scattering models in order to obtain the mean particle sizes, number densities, and the vertical extent of the two different scattering components of the Triton atmosphere. The 0.001-0.01 optical depths of about 0.17 micron particles are vertically distributed with scale heights of about 10 km throughout Triton. A number of properties of the haze particles in question suggest that they are composed of photochemically produced gases which have condensed in the cold lower atmosphere of Triton.

  10. Search for glazed surfaces on Triton

    NASA Technical Reports Server (NTRS)

    Lee, Pascal; Helfenstein, Paul; Veverka, Joseph

    1991-01-01

    The paper summarizes arguments leading to suggestions that Triton's icy surface may be unusual in texture, sith special attention given to the hypothesis of the existence of glazed areas on Triton. Results are presented of a search for an evidence of specular reflection diagnostic of 'glazed' icy surfaces on Triton, using high-resolution Voyager 2 images of three regions on Triton: the South Polar Cap Mottled Unit, the Bright Fringe, and the Frost Band. No such evidence was found in these three different terrains.

  11. Compliant Foil Seal Investigations

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret; Delgado, Irebert

    2003-01-01

    NASA Glenn Research Center has been working with Mohawk Innovative Technology, Inc. (MiTi) to develop a Compliant Foil Seal for use in gas turbine engines. MiTi was awarded phase I and phase II SBIR contracts to analyze, develop, and test foil seals. As part of the Phase II contract, MiTi delivered an 8.5 inch diameter foil seal to NASA GRC for testing. Today I will be presenting some results of testing the 8.5 inch foil seal at NASA.

  12. The Plausibility of Boiling Geysers on Triton

    NASA Technical Reports Server (NTRS)

    Duxbury, N. S.; Brown, R. H.

    1995-01-01

    A mechanism is suggested and modeled whereby there may be boiling geysers on Triton. The geysers would be of nitrogen considering that Voyager detected cryovolcanic activity, that solid nitrogen conducts heat much less than water ice, and that there is internal heat on Triton.

  13. Triton Blushes: A Clue to Global Warming?

    NASA Technical Reports Server (NTRS)

    Buratti, B. J.; Hicks, M. D.; Newburn, R. L., Jr.

    1998-01-01

    The large Neptunian satellite Triton is a geologically active body that apparently undergoes complex seasonal changes in its 165 year journey around the sun. Because it is the vehicle for the seasonal transport of volatiles, Triton's atmosphere is expected to undergo large changes in temperature and pressure on a time scale of decades.

  14. Foil Face Seal Testing

    NASA Technical Reports Server (NTRS)

    Munson, John

    2009-01-01

    In the seal literature you can find many attempts by various researchers to adapt film riding seals to the gas turbine engine. None have been successful, potential distortion of the sealing faces is the primary reason. There is a film riding device that does accommodate distortion and is in service in aircraft applications, namely the foil bearing. More specifically a foil thrust bearing. These are not intended to be seals, and they do not accommodate large axial movement between shaft & static structure. By combining the 2 a unique type of face seal has been created. It functions like a normal face seal. The foil thrust bearing replaces the normal primary sealing surface. The compliance of the foil bearing allows the foils to track distortion of the mating seal ring. The foil seal has several perceived advantages over existing hydrodynamic designs, enumerated in the chart. Materials and design methodology needed for this application already exist. Also the load capacity requirements for the foil bearing are low since it only needs to support itself and overcome friction forces at the antirotation keys.

  15. The density of triton: A prediction

    SciTech Connect

    McKinnon, W.B. ); Mueller, S. )

    1989-06-01

    The authors predict the density of Triton, as a function of radius, based on the assumptions that it was captured from solar orbit and thus has rock/ice ratio similar to that of the Pluto-Charon system. The best present estimates for Triton's radius are 1000-2000 km, and if the origin hypothesis is correct, its density should be greater than 2.0 g cm{sup {minus}3}, increasing slowly with radius. On the other hand, if Triton is an original regular satellite whose orbit has been perturbed, its density will be lower and more consistent with the derived rock fractions of other icy satellites.

  16. Comparison of Ridges on Triton and Europa

    NASA Technical Reports Server (NTRS)

    Prockter, L. M.; Pappalardo, R. .

    2003-01-01

    Triton and Europa each display a variety of ridges and associated troughs. The resemblance of double ridges on these two satellites has been previously noted [R. Kirk, pers. comm.], but as yet, the similarities and differences between these feature types have not been examined in any detail. Triton s ridges, and Europa s, exhibit an evolutionary sequence ranging from isolated troughs, through doublet ridges, to complex ridge swaths [1, 2]. Comparison of ridges on Europa to those on Triton may provide insight into their formation on both satellites, and thereby have implications for the satellites' histories.

  17. Anomalous-scattering region on Triton

    NASA Technical Reports Server (NTRS)

    Lee, Pascal; Helfenstein, Paul; Veverka, Joseph; Mccarthy, Derek

    1992-01-01

    A photometric analysis of Voyager 2 images of a broad, 'anomalous scattering region' (ASR) on Triton shows its material to differ from the average Triton regolith in being only weakly backward scattering at all Voyager 2 camera wavelengths; the ASR also displays distinctive phase-dependent green/violet color ratios and clear-filter albedo. These characteristics are used to map the global distribution of the ASR areas for which photometric coverage is incomplete. The ASR may form an almost continuous band of material that runs parallel to the Triton equator, characterized by the presence of a transparent and optically thin, seasonally-controlled veneer of well-annealed solid N2.

  18. Relativistic corrections to the triton binding energy

    SciTech Connect

    Sammarruca, F.; Xu, D.P.; Machleidt, R. )

    1992-11-01

    The influence of relativity on the triton binding energy is investigated. The relativistic three-dimensional version of the Bethe-Salpeter equation proposed by Blankenbecler and Sugar (BbS) is used. Relativistic (nonseparable) one-boson-exchange potentials (constructed in the BbS framework) are employed for the two-nucleon interaction. In a 34-channel Faddeev calculation, it is found that relativistic effects increase the triton binding energy by about 0.2 MeV. Including charge dependence (besides relativity), the final triton binding energy predictions are 8.33 and 8.16 MeV for the Bonn A and B potentials, respectively.

  19. Surface treatment using metal foil liner

    NASA Technical Reports Server (NTRS)

    Garvey, Ray

    1989-01-01

    A metal foil liner can be used to seal large area surfaces. Characteristics of the two-layer foil liner are discussed. Micrographs for foil-to-foil, foil-to-composite, visible seams, and hidden seams are examined.

  20. Beam-foil spectroscopy

    SciTech Connect

    Berry, H.G.; Hass, M.

    1982-01-01

    A brief survey of some applications of beam-foil spectroscopy is presented. Among the topics covered are lifetime and magnetic moment measurements, nuclear alignment, and polarized light production. (AIP)

  1. Volatile processes in Triton's atmosphere and surface

    NASA Technical Reports Server (NTRS)

    Lunine, J. I.

    1992-01-01

    A basic model for latitudinal transport of nitrogen is reviewed focusing on its limitations and some complications associated with surface and atmospheric physics. Data obtained by 1989 Voyager encounter with the Neptune system revealed the complexity in the pure nitrogen transport which is caused by the nonuniform albedo of the frosts. It is concluded that Triton is similar to Mars in terms of the complexity of volatile transport and to understand Triton's surface-atmosphere system, Mars may be a very good analog.

  2. A close-up view of Triton

    NASA Technical Reports Server (NTRS)

    Tsurutani, Bruce T.; Miner, Ellis D.; Collins, Stewart A.

    1990-01-01

    Triton, the only large moon in the solar system with a retrograde motion, is investigated. The moon rotates about Neptune every 5.88 days and its annual cycle lasts 165 years. The orbit of Triton is 355,000 km from Neptune and it is inclined 23 deg relative to Neptune's equator. The precession of its orbital plane causes complications in its seasonal progression. Triton has a radius of 1353 km and a density of 2.07 gm/cu cm. Triton is believed to have a core of rock surrounded by water ice and a surface veneer of methane and nitrogen ice. The bright haze in its atmosphere could be small grains of particulates. Triton's surface features suggest that the moon should have remained molten until about 1 billion years ago. In order to explain the active geyser-like plumes observed near the subsolar latitude of about 50 deg south, various mechanisms are suggested including explosive escape of nitrogen gas, surface winds, and buoyancy of warmer gas. Voyager 2, which left Neptune and Triton in August 1989 and is now moving out of the solar system, is expected to provide the first glimpses of interstellar material.

  3. SNS Injection Foil Experience

    SciTech Connect

    Cousineau, Sarah M; Galambos, John D; Kim, Sang-Ho; Ladd, Peter; Luck, Chris; Peters, Charles C; Polsky, Yarom; Shaw, Robert W; Macek, Robert James; Raparia, Deepak; Plum, Michael A

    2010-01-01

    The Spallation Neutron Source comprises a 1 GeV, 1.4 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H0 excited states created during the H charge exchange injection into the accumulator ring, the stripper foil is located inside one of the chicane dipoles. This has some interesting consequences that were not fully appreciated until the beam power reached about 840 kW. One consequence was sudden failure of the stripper foil system due to convoy electrons stripped from the incoming H beam, which circled around to strike the foil bracket and cause bracket failure. Another consequence is that convoy electrons can reflect back up from the electron catcher and strike the foil and bracket. An additional contributor to foil system failure is vacuum breakdown due to the charge developed on the foil by secondary electron emission. In this paper we will detail these and other interesting failure mechanisms, and describe the improvements we have made to mitigate them.

  4. The Atmospheric Structure of Triton and Pluto

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    1998-01-01

    The goal of this research was to better determine the atmospheric structures of Triton and Pluto through further analysis of three occultation data sets obtained with the Kuiper Airborne Observatory (KAO.) As the research progressed, we concentrated our efforts on the Triton data, as this appeared to be the most fruitful. Three papers have been prepared as a result of this research. The first paper presents new results about Triton's atmospheric structure from the analysis of all ground-based stellar occultation data recorded to date, including one single-chord occultation recorded on 1993 July 10 and nine occultation lightcurves from the double-star event on 1995 August 14. These stellar occultation observations made both in the visible and in the infrared have good spatial coverage of Triton, including the first Triton central-flash observations, and are the first data to probe the altitude level 20-100 km on Triton. The small-planet lightcurve model of J. L. Elliot and L. A. Young was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude, indicating that Triton's atmosphere is spherically symmetric at approximately 50 km altitude to within the error of the measurements; however, asymmetry observed in the central flash indicates the atmosphere is not homogenous at the lowest levels probed (approximately 20 km altitude). From the average of the 1995 occultation data, the equivalent isothermal temperature of the atmosphere is 47 plus or minus 1 K and the atmospheric pressure at 1400 km radius (approximately 50 km altitude) is 1.4 plus or minus 0.1 microbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989. The atmospheric temperature from the occultation is 5 K colder than that predicted by the model and the observed pressure is a factor of 1.8 greater than the

  5. Foil implosion studies on PEGASUS

    SciTech Connect

    Cochrane, J.C.; Bartsch, R.R.; Begay, F.; Kruse, H.W.; Oona, H.; Parker, J.V.; Turchi, P.J.

    1989-01-01

    PEGASUS is a 1.5 MJ capacitor bank facility used in the Los Alamos Trailmaster foil implosion program. The experiments on this facility are to serve as a diagnostic testbed and foil physics benchmark for foil implosions with explosive generators as drivers. During the first year of operation, foil implosions have been driven by discharging the bank directly into a very thin Aluminum 2500 /angstrom/ thick free-standing foil without any pulse sharpening techniques; so-called ''direct drive.''These direct drive experiments have served as initial tests to optimize bank performance and foil implosion experimental techniques. The results to date are presented below. 1 ref., 2 figs.

  6. The phase composition of Triton's polar caps

    NASA Technical Reports Server (NTRS)

    Duxbury, N. S.; Brown, R. H.

    1993-01-01

    Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them.

  7. Triton stellar occultation candidates - 1992-1994

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. T.

    1992-01-01

    A search for Triton stellar occultation candidates for the period 1992-1994 has been completed with CCD strip-scanning observations. The search reached an R magnitude of about 17.4 and found 129 candidates within 1.5 arcsec of Triton's ephemeris during this period. Of these events, around 30 occultations are expected to be visible from the earth, indicating that a number of Triton occultation events should be visible from major observatories. Even the faintest of the present candidate events could produce useful occultation data if observed with a large enough telescope. The present astrometric accuracy is inadequate to identify which of these appulse events will produce occultations on the earth; further astrometry is needed to refine the predictions for positive occultation identification. To aid in selecting candidates for additional astrometric and photometric studies, finder charts and earth-based visibility charts for each event are included.

  8. The phase composition of Triton's polar caps

    NASA Astrophysics Data System (ADS)

    Duxbury, N. S.; Brown, R. H.

    1993-08-01

    Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them.

  9. The Phase Composition of Triton's Polar Caps.

    PubMed

    Duxbury, N S; Brown, R H

    1993-08-01

    Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them. PMID:17757213

  10. Color Sequence of Triton Approach Images

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Triton Voyager 2 approach sequence with latitude-longitude grid superposed. The color image was reconstructed by making a computer composite of three black and white images taken through red, green, and blue filters. Details on Triton's surface unfold dramatically in this sequence of approach images. South Pole near the bottom of the images at the convergence of lines of longitude. Resolution changes from about 60 km/pixel (37 mi/pixel) in the image at upper left taken from a distance of 500,000 (311,000 mi) to about 5 km/pixel (3.1 mi/pixel) for the image at lower right. Global and regional albedo features are visible in all of the images. The albedo features can be tracked in successive images and show that Triton has undergone about 3/4 of a rotation during the 4.3-day interval over which these images were obtained. A southern polar cap of bright pink, yellow, and white materials covers nearly all of the southern hemisphere; these materials consist of nitrogen ice with traces of other substances, including frozen methane and carbon monoxide. Feeble ultraviolet radiation from the sun is thought to act on methane to cause chemical reactions to the pinkish yellowish substances. At the time of the Voyager 2 flyby (Jan. 1989) Triton's southern hemisphere was starting the summer season and the South Pole was canted toward the sun day and night, such that the polar cap was sublimating under the relatively 'hot' summer sun (surface temperature about 38 K, about -391 degree F). Numerous dark streaks on the southern polar nitrogen-ice cap are thought to consist of dark dust deposited by prevailing winds in Triton's tenuous nitrogen atmosphere. A bluish band, seen in all of the images, nearly circumstances Triton's equator; this band is thought to consist of fairly nitrogen frost, perhaps deposited in the decade prior to Voyager 2's flyby.

  11. Triton's surface-atmosphere energy balance

    NASA Technical Reports Server (NTRS)

    Stansberry, John A.; Yelle, Roger V.; Lunine, Jonathan I.; Mcewen, Alfred S.

    1992-01-01

    A model encompassing the turbulent transfer of sensible heat as well as insolation, reradiation, and latent heat transport is presently used to investigate the energetics of the surface-atmosphere system of Triton. Under the assumption of a physically plausible range of heat transfer coefficients, the atmospheric temperature 1 km above the surface is found to be 1-3 K hotter than the Triton surface. The observed N2 frosts must have an emissivity lower than unity in order to match a frost temperature at the surface of about 38 K.

  12. A massive early atmosphere on Triton

    NASA Technical Reports Server (NTRS)

    Lunine, Jonathan I.; Nolan, Michael C.

    1992-01-01

    The idea of an early greenhouse atmosphere for Triton is presented and the conditions under which it may have been sustained are quantified. The volatile content of primordial Triton is modeled, and tidal heating rates are assessed to set bounds on the available energy. The atmospheric model formalism is presented, and it is shown how a massive atmosphere could have been raised by modest tidal heating fluxes. The implications of the model atmospheres for the atmospheric escape rates, the chemical evolution, and the cratering record are addressed.

  13. V photometry of Titania, Oberon, and Triton

    SciTech Connect

    Goguen, J.D.; Hammel, H.B.; Brown, R.H.

    1989-02-01

    The phase angle and orbital brightness variations of Titania, Oberon, and Triton are presently obtained through analysis of V filter photometry obtained at Mauna Kea in 1982-1983. While Titania and Oberon exhibit magnitude variations with phase angle comparable to those of low-to-moderate albedo asteroids observed within several deg of opposition, Triton's phase variation is distinctly different from these and has a phase coefficient consistent with either a high-albedo regolith or an optically thick nonparticulate scattering layer (perhaps an atmosphere, or an ocean). A low-albedo regolith cannot on the strength of these data be ruled out, however. 39 references.

  14. Monolithic exploding foil initiator

    DOEpatents

    Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

    2012-10-23

    A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

  15. Role of Internal Heat Source for Eruptive Plumes on Triton

    NASA Technical Reports Server (NTRS)

    Duxbury, N. S.; Brown, R. H.

    1996-01-01

    For the first time the role of the internal heat source, due to radioactive decay in Triton's core, is investigate with respect to geyser-like plumes...A new mechanism of energy supply to the Tritonian eruptive plumes is proposed...We present the critical values of these parameters for Triton. A possible origin of the subsurface vents on Triton is also suggested.

  16. Triton College Marketing Plan '85-'86.

    ERIC Educational Resources Information Center

    Fonte, Richard, Ed.; Leach, Ernie, Ed.

    Prepared in response to shifts in the student body make-up and demographic changes in the school district, this report provides an in-depth analysis of environmental conditions faced by Triton College (Illinois) and presents a specific marketing plan developed in response to the identified trends. The first sections of the report focus on trends…

  17. Restaurant Training Recipe At Triton College

    ERIC Educational Resources Information Center

    Quagliano, Joseph

    1974-01-01

    The successful restaurant training program at Triton College (Illinois) involves a broadly based, two-year curriculum offering practical training in nearly all the areas associated with a comprehensive food operation--management, food preparation, menu planning, nutrition, personnel vending, dining room service, and cost control. (Author/EA)

  18. Triton's surface-atmosphere energy balance

    USGS Publications Warehouse

    Stansberry, J.A.; Yelle, R.V.; Lunine, J.I.; McEwen, A.S.

    1992-01-01

    We explore the energetics of Triton's surface-atmosphere system using a model that includes the turbulent transfer of sensible heat as well as insolation, reradiation, and latent heat transport. The model relies on a 1?? by 1?? resolution hemispheric bolometric albedo map of Triton for determining the atmospheric temperature, the N2 frost emissivity, and the temperatures of unfrosted portions of the surface consistent with a frost temperature of ???38 K. For a physically plausible range of heat transfer coefficients, we find that the atmospheric temperature roughly 1 km above the surface is approximately 1 to 3 K hotter than the surface. Atmospheric temperatures of 48 K suggested by early analysis of radio occultation data cannot be obtained for plausible values of the heat transfer coefficients. Our calculations indicate that Triton's N2 frosts must have an emissivity well below unity in order to have a temperature of ???38 K, consistent with previous results. We also find that convection over small hot spots does not significantly cool them off, so they may be able to act as continous sources of buoyancy for convective plumes, but have not explored whether the convection is vigorous enough to entrain particulate matter thereby forming a dust devil. Our elevated atmospheric temperatures make geyser driven plumes with initial upward velocities ???10 m s-1 stagnate in the lower atmosphere. These "wimpy" plumes provide a possible explanation for Triton's "wind streaks.". ?? 1992.

  19. Triton College Faculty Recruitment Action Plan (FRAP).

    ERIC Educational Resources Information Center

    Triton Coll., River Grove, IL.

    Triton College's (Illinois) Faculty Recruitment Action Plan (FRAP) provides a detailed guide to hiring new faculty, focusing on the desired characteristics of new faculty; marketing and recruitment strategies; employment incentives; the application, interviewing, and selection process; new faculty orientation; a timeline for implementation; cost…

  20. Photometric diversity of terrains on Triton

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Veverka, J.; Helfenstein, P.; Lee, P.

    1994-01-01

    Voyager disk-resolved images of Triton in the violet (0.41 micrometers) and green (0.56 micrometer wavelengths have been analyzed to derive the photometric characteristics of terrains on Triton. Similar conclusions are found using two distinct but related definitions of photometric units, one based on color ratio and albedo properties (A. S. McEwen, 1990), the other on albedo and brightness ratios at different phase angles (P. Lee et al., 1992). A significant diversity of photometric behavior, much broader than that discovered so far on any other icy satellite, occurs among Triton's terrains. Remarkably, differences in photometric behavior do not correlate well with geologic terrain boundaries defined on the basis of surface morphology. This suggests that in most cases photometric properties on Triton are controlled by thin deposits superposed on underlying geologic units. Single scattering albedos are 0.98 or higher and asymmetry factors range from -0.35 to -0.45 for most units. The most distinct scattering behavior is exhibited by the reddish northern units already identified as the Anomalously Scattering Region (ASR), which scatters light almost isotropically with g = -0.04. In part due to the effects of Triton's clouds and haze, it is difficult to constrain the value of bar-theta, Hapke's macroscopic roughness parameter, precisely for Triton or to map differences in bar-theta among the different photometric terrains. However, our study shows that Triton must be relatively smooth, with bar-theta less than 15-20 degs and suggests that a value of 14 degs is appropriate. The differences in photometric characteristics lead to significantly different phase angle behavior for the various terrains. For example, a terrain (e.g., the ASR) that appears dark relative to another at low phase angles will reverse its contrast (become relatively brighter) at larger phase angles. The photometric parameters have been used to calculate hemispherical albedos for the units and to

  1. Stellar Occultation Probe of Triton's Atmosphere

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    1998-01-01

    The goals of this research were (i) to better characterize Triton's atmospheric structure by probing a region not well investigated by Voyager and (ii) to begin acquiring baseline data for an investigation of the time evolution of the atmosphere which will set limits on the thermal conductivity of the surface and the total mass of N2 in the atmosphere. Our approach was to use observations (with the Kuiper Airborne Observatory) of a stellar occultation by Triton that was predicted to occur on 1993 July 10. As described in the attached reprint, we achieved these objectives through observation of this occultation and a subsequent one with the KAO in 1995. We found new results about Triton's atmospheric structure from the analysis of the two occultations observed with the KAO and ground-based data. These stellar occultation observations made both in the visible and infrared, have good spatial coverage of Triton including the first Triton central-flash observations, and are the first data to probe the 20-100 km altitude level on Triton. The small-planet light curve model of Elliot and Young (AJ 103, 991-1015) was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude indicating that Triton's atmosphere is spherically symmetric at approximately 50 km altitude to within the error of the measurements. However, asymmetry observed in the central flash indicates the atmosphere is not homogeneous at the lowest levels probed (approximately 20 km altitude). From the average of the 1995 occultation data, the equivalent-isothermal temperature of the atmosphere is 47 +/- 1 K and the atmospheric pressure at 1400 km radius (approximately 50 km altitude) is 1.4 +/- 0.1 microbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989 (Strobel et al, Icarus 120, 266-289). The atmospheric

  2. Process for anodizing aluminum foil

    SciTech Connect

    Ball, J.A.; Scott, J.W.

    1984-11-06

    In an integrated process for the anodization of aluminum foil for electrolytic capacitors including the formation of a hydrous oxide layer on the foil prior to anodization and stabilization of the foil in alkaline borax baths during anodization, the foil is electrochemically anodized in an aqueous solution of boric acid and 2 to 50 ppm phosphate having a pH of 4.0 to 6.0. The anodization is interrupted for stabilization by passing the foil through a bath containing the borax solution having a pH of 8.5 to 9.5 and a temperature above 80/sup 0/ C. and then reanodizing the foil. The process is useful in anodizing foil to a voltage of up to 760 V.

  3. Solar control of the upper atmosphere of Triton

    NASA Technical Reports Server (NTRS)

    Lyons, James R.; Yung, Yuk L.; Allen, Mark

    1992-01-01

    If the upper atmosphere and ionosphere of Triton are controlled by precipitation of electrons from Neptune's magnetosphere as previously proposed, Triton could have the only ionosphere in the solar system not controlled by solar radiation. However, a new model of Triton's atmosphere, in which only solar radiation is present, predicts a large column of carbon atoms. With an assumed, but reasonable, rate of charge transfer between N2(+) and C, a peak C(+) abundance results that is close to the peak electron densities measured by Voyager in Triton's ionosphere. These results suggest that Triton's upper atmospheric chemistry may thus be solar-controlled. Measurement of key reaction rate constants, currently unknown or highly uncertain at Triton's low temperatures, would help to clarify the chemical and physical processes occurring in Triton's atmosphere.

  4. Triton stellar occultation candidates: 1995-1999

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. L.

    1995-01-01

    We have completed a search for candidates for stellar occultations by Triton over the years 1995-1999. CCd strip scan images provided star positions in the relevant sky area to a depth of about 17.5 R magnitude. Over this time period, we find that Triton passes within 1.0 arcsec of 75 stars. Appulses with geocentric minimum separations of less than 0.35 arcsec will result in stellar occultations, but further astrometry and photometry is necessary to refine individual predictions for identification of actual occultations. Finder charts are included to aid in further studies and prediction refinement. The two most promising potential occultations, Tr176 and Tr180, occur in 1997.

  5. Chemical processes in Triton's atmosphere and surface

    NASA Astrophysics Data System (ADS)

    Delitsky, M. L.; Thompson, W. R.

    1987-05-01

    Liquid solutions of N2 containing up to one-third CH4 can exist on Triton's surface in regions T > 62.5K. More generally, subsurface oceans of N2 solution are expected to be stable beneath overlying, thermally insulating, less dense layers of the abundant light hydrocarbon products of radiochemical synthesis: C2H6, C3H8, and C4H10. Cosmic rays are the main source of energy, capable of producing synthesis of organic compounds from N2 - CH4 solutions on the surface. For baseline Triton models with R = 2500 km, ρ = 2.1 g cm-3, and Ts = 65 or 55K, respectively, 4×10-3 or 7×10-3erg cm-2sec-1 (49 or 87% of the total incident flux) is deposited within a few meters below the surface. Using yields from laboratory experiments, the authors estimate the quantities of products produced.

  6. Voyager disk-integrated photometry of Triton

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Helfenstein, P.; Verbiscer, A.; Veverka, J.; Brown, R. H.; Goguen, J.; Johnson, T. V.

    1990-01-01

    Hapke's (1981) photometric model has been combined with a plane-parallel thin atmospheric haze model to describe Voyager whole-disk observations of Triton, in the violet, blue, and green wavelength bands, in order to obtain estimates of Triton's geometric albedo, phase integral, and Bond albedo. Phase angle coverage in these filters ranging from about 12 to 159 deg was obtained by combining narrow- and wide-angle camera images. An upturn in the data at the highest phase angles observed can be explained by including scattering in a thin atmospheric haze layer with optical depths systematically decreasing with wavelength from about 0.06 in the violet to 0.03 for the green filter data.

  7. Triton's plumes - The dust devil hypothesis

    NASA Astrophysics Data System (ADS)

    Ingersoll, Andrew P.; Tryka, Kimberly A.

    1990-10-01

    Triton's plumes are narrow columns 10 km in height, with tails extending horizontally for distances over 100 km. This structure suggests that the plumes are an atmospheric rather than a surface phenomenon. The closest terrestrial analogs may be dust devils, which are atmospheric vortices originating in the unstable layer close to the ground. Since Triton has such a low surface pressure, extremely unstable layers could develop during the day. Patches of unfrosted ground near the subsolar point could act as sites for dust devil formation because they heat up relative to the surrounding nitrogen frost. The resulting convection would warm the atmosphere to temperatures of 48 k or higher, as observed by the Voyager radio science team. Assuming that velocity scales as the square root of temperature difference times the height of the mixed layer, a velocity of 20 m/sec is derived for the strongest dust devils on Triton. Winds of this speed could raise particles provided they are a factor of 1000 to 10,000 less cohesive than those on earth.

  8. Acceleration of tritons with a compact cyclotron

    NASA Astrophysics Data System (ADS)

    Wegmann, H.; Huenges, E.; Muthig, H.; Morinaga, H.

    1981-01-01

    With the compact cyclotron at the Faculty of the Technical University of Munich, tritons have been accelerated to an energy of 7 MeV. A safe and reliable operation of the gas supply for the ion source was obtained by a new tritium storage system. A quantity of 1500 Ci tritium is stored by two special Zr-Al getter pumps in a non-gaseous phase. The tritium can be released in well-defined amounts by heating the getter material. During triton acceleration the pressure in the cyclotron vacuum chamber is maintained only by a large titanium sputter-ion pump, thus forming a closed vacuum system without any exhaust of tritium contaminated gas. Any tritium contaminations in the air can be detected by an extremely sensitive tritium monitoring system. The triton beam with a maximum intensity of 30 μA has been used so far to produce neutron-rich radioisotopes such as 28Mg, 43K or 72Zn, which are successfully applied in tracer techniques in the studies of biological systems.

  9. Comparative Planetary Atmospheres of Pluto and Triton

    NASA Astrophysics Data System (ADS)

    Strobel, D. F.; Zhu, X.

    2015-10-01

    Both atmospheres of Pluto and Neptune's largest satellite Triton have cold surfaces with similar surface gravities and atmospheric surface pressures. We have updated the Zhu et al.Icarus 228 , 301, 2014) model for Pluto's atmosphere by adopting Voigt line profiles in the radiation code with the latest spectral database and extended the model to Triton's atmosphere by including additional parameterized heating due to the magnetospheric electron energy deposition. Numerical experiments show that the escape rate of an atmosphere for an icy planetary body similar to Pluto or Triton is quite sensitive to the methane abundance and planetary surface gravity. Together this leads to a cumulative effect on the density variation with the altitude that significantly changes the atmospheric scale height at the exobase together with the exobase altitude. The atmospheric thermal structure near the exobase is sensitive to the atmospheric escape rate only when it is significantly greater than 10 26 molecules s-1 above which an enhanced escape rate corresponds to a stronger radial velocity that adiabatically cools the atmosphere to a lower temperature.

  10. Chemical investigation of Titan and Triton tholins

    NASA Technical Reports Server (NTRS)

    Mcdonald, Gene D.; Thompson, W. R.; Heinrich, Michael; Khare, Bishun N.; Sagan, Carl

    1994-01-01

    We report chromatographic and spectroscopic analyses of both Titan and Triton tholins, organic solids made from the plasma irradiation of 0.9:0.1 and 0.999:0.001 N2/CH4 gas mixtures, respectively. The lower CH4 mixing ratio leads to a nitrogen-richer tholin (N/C greater than 1), probably including nitrogen heterocyclic compounds. Unlike Titan tholin, bulk Triton tholin is poor in nitriles. From high-pressure liquid chromatography, ultraviolet and infrared spectroscopy, and molecular weight estimation by gel filtration chromatography, we conclude that (1) several H2O-soluble fractions, each with distinct UV and IR spectral signatures, are present, (2) these fractions are not identical in the two tholins, (3) the H2O-soluble fractions of Titan tholins do not contain significant amounts of nitriles, despite the major role of nitriles in bulk Titan tholin, and (4) the H2O-soluble fractions of both tholins are mainly molcules containing about 10 to 50 (C + N) atoms. We report yields of amino acids upon hydrolysis of Titan and Triton tholins. Titan tholin is largely insoluble in the putative hydrocarbon lakes or oceans on Titan, but can yield the H2O-soluble species investigated here upon contact with transient (e.g., impact-generated) liquid water.

  11. Triton's plumes - The dust devil hypothesis

    NASA Technical Reports Server (NTRS)

    Ingersoll, Andrew P.; Tryka, Kimberly A.

    1990-01-01

    Triton's plumes are narrow columns 10 km in height, with tails extending horizontally for distances over 100 km. This structure suggests that the plumes are an atmospheric rather than a surface phenomenon. The closest terrestrial analogs may be dust devils, which are atmospheric vortices originating in the unstable layer close to the ground. Since Triton has such a low surface pressure, extremely unstable layers could develop during the day. Patches of unfrosted ground near the subsolar point could act as sites for dust devil formation because they heat up relative to the surrounding nitrogen frost. The resulting convection would warm the atmosphere to temperatures of 48 k or higher, as observed by the Voyager radio science team. Assuming that velocity scales as the square root of temperature difference times the height of the mixed layer, a velocity of 20 m/sec is derived for the strongest dust devils on Triton. Winds of this speed could raise particles provided they are a factor of 1000 to 10,000 less cohesive than those on earth.

  12. Triton - Stratospheric molecules and organic sediments

    NASA Technical Reports Server (NTRS)

    Thompson, W. Reid; Singh, Sushil K.; Khare, B. N.; Sagan, Carl

    1989-01-01

    Continuous-flow plasma discharge techniques show production rates of hydrocarbons and nitriles in N2 + CH4 atmospheres appropriate to the stratosphere of Titan, and indicate that a simple eddy diffusion model together with the observed electron flux quantitatively matches the Voyager IRIS observations for all the hydrocarbons, except for the simplest ones. Charged particle chemistry is very important in Triton's stratosphere. In the more CH4-rich case of Titan, many hydrocarbons and nitriles are produced in high yield. If N2 is present, the CH4 fraction is low, but hydrocarbons and nitriles are produced in fair yield, abundances of HCN and C2H2 in Triton's stratosphere exceed 10 to the 19th molecules/sq cm per sec, and NCCN, C3H4, and other species are predicted to be present. These molecules may be detected by IRIS if the stratosphere is as warm as expected. Both organic haze and condensed gases will provide a substantial UV and visible opacity in Triton's atmosphere.

  13. Compliant Foil Seal Investigations

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret; Delgado, Irebert

    2004-01-01

    Room temperature testing of an 8.5 inch diameter foil seal was conducted in the High Speed, High Temperature Turbine Seal Test Rig at the NASA Glenn Research Center. The seal was operated at speeds up to 30,000 rpm and pressure differentials up to 75 psid. Seal leakage and power loss data will be presented and compared to brush seal performance. The failure of the seal and rotor coating at 30,000 rpm and 15 psid will be presented and future development needs discussed.

  14. Submicron, unbacked, shaped metal foils

    SciTech Connect

    Duchane, D.V.; Barthell, B.L.

    1983-01-01

    A method was developed to produce unbacked, shaped metal foils in sub-micron thicknesses. This process utilizes a temporary substrate consisting of a water-soluble polymer film as a base for the electron-beam deposition of the metal layer. After formation of the metal foil, the polymer is removed by immersion of the assembly in water. Unbacked metal-foil cylinders as thin as 0.17 ..mu..m with extremely smooth, wrinkle-free surfaces have been produced by this technique. Polyvinyl alcohol was an excellent substrate. Aluminum foils were produced.

  15. Coupling of volatile transport and internal heat flow on Triton

    NASA Technical Reports Server (NTRS)

    Brown, Robert H.; Kirk, Randolph L.

    1994-01-01

    Recently Brown et al. (1991) showed that Triton's internal heat source could amount to 5-20% of the absorbed insolation on Triton, thus significantly affecting volatile transport and atmospheric pressure. Subsequently, Kirk and Brown (1991a) used simple analytical models of the effect of internal heat on the distribution of volatiles on Triton's surface, confirming the speculation of Brown et al. that Triton's internal heat flow could strongly couple to the surface volatile distribution. To further explore this idea, we present numerical models of the permanent distribution of nitrogen ice on Triton that include the effects of sunlight, the two-dimensional distribution of internal heat flow, the coupling of internal heat flow to the surface distribution of nitrogen ice, and the finite viscosity of nitrogen ice. From these models we conclude that: (1) The strong vertical thermal gradient induced in Triton's polar caps by internal heat-flow facilitates viscous spreading to lower latitudes, thus opposing the poleward transport of volatiles by sunlight, and, for plausible viscosities and nitrogen inventories, producing permanent caps of considerable latitudinal extent; (2) It is probable that there is a strong coupling between the surface distribution of nitrogen ice on Triton and internal heat flow; (3) Asymmetries in the spatial distribution of Triton's heat flow, possibly driven by large-scale, volcanic activity or convection in Triton's interior, can result in permanent polar caps of unequal latitudinal extent, including the case of only one permanent polar cap; (4) Melting at the base of a permanent polar cap on Triton caused by internal heat flow can significantly enhance viscous spreading, and, as an alternative to the solid-state greenhouse mechanism proposed by Brown et al. (1990), could provide the necessary energy, fluids, and/or gases to drive Triton's geyser-like plumes; (5) The atmospheric collapse predicted to occur on Triton in the next 20 years

  16. Rhenium-Foil Witness Cylinders

    NASA Technical Reports Server (NTRS)

    Knight, B. L.

    1992-01-01

    Cylindrical portion of wall of combustion chamber replaced with rhenium foil mounted on holder. Rhenium oxidizes without melting, indicating regions of excess oxidizer in combustion-chamber flow. Rhenium witness foils also useful in detecting excess oxygen and other oxidizers at temperatures between 2,000 and 3,600 degrees F in burner cores of advanced gas-turbine engines.

  17. Consequences of FOIL for Undergraduates

    ERIC Educational Resources Information Center

    Koban, Lori; Sisneros-Thiry, Simone

    2015-01-01

    FOIL is a well-known mnemonic that is used to find the product of two binomials. We conduct a large sample (n = 252) observational study of first-year college students and show that while the FOIL procedure leads to the accurate expansion of the product of two binomials for most students who apply it, only half of these students exhibit conceptual…

  18. Triton College and General Motors: The Partnership Model.

    ERIC Educational Resources Information Center

    Fonte, Richard; Magnesen, Vernon

    1983-01-01

    The cooperative training program between Illinois's Triton College and General Motors is described. Illustrates the mutual benefits of this problem and recommends that other colleges follow suit. (NJ)

  19. On the microphysical state of the surface of Triton

    NASA Technical Reports Server (NTRS)

    Eluszkiewicz, Janusz

    1991-01-01

    The microphysical processes involved in the pressureless sintering of particulate materials and the physical conditions likely to prevail on Triton are examined in order to investigate the processes leading to the frost metamorphism on Triton. It is argued that the presence of a well-annealed transparent nitrogen layer offers a natural explanation for most of what is seen on the surface of Triton; results of observations suggest that such a layer can form on Triton at 37 K on a seasonal time scale (about 100 earth years), provided the initial grain diameter is less than 1 micron. Grains up to 10 microns are allowed if grain growth does not hinder densification.

  20. Secondary fusion coupled deuteron/triton transport simulation and thermal-to-fusion neutron convertor measurement

    SciTech Connect

    Wang, G. B.; Wang, K.; Liu, H. G.; Li, R. D.

    2013-07-01

    A Monte Carlo tool RSMC (Reaction Sequence Monte Carlo) was developed to simulate deuteron/triton transportation and reaction coupled problem. The 'Forced particle production' variance reduction technique was used to improve the simulation speed, which made the secondary product play a major role. The mono-energy 14 MeV fusion neutron source was employed as a validation. Then the thermal-to-fusion neutron convertor was studied with our tool. Moreover, an in-core conversion efficiency measurement experiment was performed with {sup 6}LiD and {sup 6}LiH converters. Threshold activation foils was used to indicate the fast and fusion neutron flux. Besides, two other pivotal parameters were calculated theoretically. Finally, the conversion efficiency of {sup 6}LiD is obtained as 1.97x10{sup -4}, which matches well with the theoretical result. (authors)

  1. The wavelength dependence of Triton's light curve

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Veverka, J.; Helfenstein, P.; Mcewen, A.

    1991-01-01

    Using Voyager observations, it is demonstrated that Triton's orbital light curve is strongly wavelength-dependent, a characteristic which readily explains some of the apparent discrepancies among pre-Voyager telescopic measurements. Specifically, a light curve amplitude (peak to peak) is found that decreases systematically with increasing wavelength from about 0.08 magnitude (peak to peak) near 200 nm to less than 0.02 magnitude near 1000 nm. Peak brightness occurs near 90 deg orbital longitude (leading hemisphere). The brightness variation across this hemisphere is close to sinusoidal; the variation across the darker hemisphere is more complex. The decrease in light curve amplitude with increasing wavelength appears to be due to a decrease in contrast among surface markings, rather than to atmospheric obscuration. The model also explains the observed decrease in the amplitude of Triton's light curve at visible wavelengths over the past decade, a decrease related to the current migration of the subsolar latitude toward the south pole; it is predicted that this trend will continue into the 1990s.

  2. Global color and albedo variations on Triton

    NASA Technical Reports Server (NTRS)

    Mcewen, Alfred S.

    1990-01-01

    Global multispectral mosaics of Triton have been produced from Voyager approach images; six spectral units are defined and mapped. The margin of the south polar cap (SPC) is scalloped and ranges in latitude from + 10 deg to -30 deg. A bright fringe is closely associated with the cap's margin; form it, diffuse bright rays extend north-northeast for hundreds of kilometers. Thus, the rays may consist of fringe materials that were redistributed by northward-going Coriolis-deflected winds. From 1977 to 1989, Triton's full-disk spectrum changed from markedly red and UV-dark to nearly neutral white and UV-bright. This spectral change can be explained by new deposition of nitrogen frost over both the northern hemisphere and parts of a formerly redder SPC. Frost deposition in the southern hemisphere during southern summer is possible over relatively high albedo areas of the cap (Stansberry et al., 1990), which helps to explain the apparent stability of the unexpectedly large SPC and the presence of the bright fringe.

  3. Consequences of FOIL for undergraduates

    NASA Astrophysics Data System (ADS)

    Koban, Lori; Sisneros-Thiry, Simone

    2015-02-01

    FOIL is a well-known mnemonic that is used to find the product of two binomials. We conduct a large sample (n = 252) observational study of first-year college students and show that while the FOIL procedure leads to the accurate expansion of the product of two binomials for most students who apply it, only half of these students exhibit conceptual understanding of the procedure. We generalize this FOIL dichotomy and show that the ability to transfer a mathematical property from one context to a less familiar context is related to both procedural success and attitude towards math.

  4. Diapirs and cantaloupes: Layering and overturn of Triton's crust

    NASA Technical Reports Server (NTRS)

    Schenk, P.; Jackson, M. P. A.

    1993-01-01

    It has recently been proposed that cantaloupe terrain formed as a result of instability and overturn (i.e., diapirism) of Triton's crust. Morphologic evidence implicates compositional layering within Triton's crust as the driving mechanism for the overturn. Here, we review the morphologic evidence for this origin and evaluate some of the implications.

  5. New astrometric observations of Triton in 2007-2009

    NASA Astrophysics Data System (ADS)

    Qiao, R. C.; Zhang, H. Y.; Dourneau, G.; Yu, Y.; Yan, D.; Shen, K. X.; Cheng, X.; Xi, X. J.; Hu, X. Y.; Wang, S. H.

    2014-06-01

    Astrometric positions of the Neptunian satellite Triton with a visual magnitude of 13.5 were obtained during three successive oppositions in 2007, 2008 and 2009. A total of 1095 new observed positions of Triton were collected during 46 nights of observations, involving eight missions and three telescopes. We compared our observations to the best ephemerides of Triton available now. This comparison has shown that our observations present a high level of accuracy as they provide standard deviations of residuals hardly higher than 50 mas and mean residuals lower than 30 mas, corresponding to about only 500 km in the position of the very distant satellite Triton. Moreover, we have compared most of the different planetary ephemerides of Neptune available now as well as two recent orbit models of Triton. These new comparisons have clearly shown the differences between all of these ephemerides which can be significant and that are presented in this work.

  6. Three-triton states in {sup 9}Li

    SciTech Connect

    Muta, K.; Furumoto, T.; Ichikawa, T.; Itagaki, N.

    2011-09-15

    We investigate whether three-triton states appear or not in excited states of {sup 9}Li. We also search for a signature of the gaslike three-triton state, which is partly an analogy to the the case of the three-{alpha} state in {sup 12}C (Hoyle state). For this purpose, we use both three-triton and {alpha}+t+n+n wave functions to describe the low-lying states of {sup 9}Li and take into account the coupling effect between them. We show that the states in which the three-triton components dominate indeed appear below the three-triton threshold energy, although the root-mean-square radii of those states are not so much expanded in comparison with the gaslike state of three {alpha}'s.

  7. Triton, Pluto, and the origin of the solar system

    NASA Astrophysics Data System (ADS)

    Lunine, J. I.

    1993-08-01

    Planets may represent a commmon by-product of star formation, and thus may be a source of physical and chemical clues to the origin of the solar system. This paper discusses the molecular composition of Triton and Pluto, two of the most distant objects of the solar system. Particular consideration is given to the new findings (Cruikshank et al., 1993; Owen et al., 1993) of methane ice in concentrations from 0.05 percent (Triton) to 1.5 percent (Pluto) and carbon monoxide ice in concentrations from 0.1 percent (Triton) to 0.5 percent (Pluton), relative to nitrogen ice. The high abundance of nitrogen suggests a scenario of early outgassing of both Triton and Pluto, followed by substantial loss of CO. The nitrogen seen today on the two bodies must have been produced later in the histories of Pluto and Triton from a nitrogen-bearing molecule much less volatile than molecular nitrogen.

  8. A New Model for the Seasonal Evolution of Triton

    NASA Astrophysics Data System (ADS)

    Forget, F.; Decamp, N.; Berthier, J.; Le Guyader, C.

    2000-10-01

    The seasonal evolution of Triton's surface and atmosphere remains poorly understood. No model [1] has been able to fully reproduce the main characterictics of the Voyager 2 observations in 1989 in combination with the "Global warming" recently inferred from stellar occultations [2]. Within this context, we have developped a new thermal model to study the seasonal nitrogen cycle on Triton. The model is the surface part of a Triton atmosphere General circulation model developped at LMD [3]. The nitrogen cycle was found to be very sensitive to Triton complex seasonal variations of the subsolar point latitude, especially during the current decade (south summer solstice). Since only pre-Voyager formulations were available for such a study, this has motivated some new calculations of Triton's motion based on more recent rotationnal elements combined with a relatively complete dynamic solution [4] adapted to Triton. A new analytic formulation suitable for climate modelling has been derived. On this basis, we wish to suggest a new, realistic scenario to explain Triton's apparence and evolution based on solar-induced variation of the frost albedo. Such variations have been observed in Mars CO2 ice seasonal polar caps [5]. Although they seem to result from complex microphysical behavior, they are likely to occur on Triton since both Triton and Mars polar caps are composed of weakly absorbing ice (N2 or CO2) in vapor pressure equilibrium with the main constituant of the atmosphere. [1] e.g. Hansen and Paige, Icarus 99, 273-288 (1992); Brown and Kirk, J. Geophys. Res. 99, 1965-1981 (1994); Spencer and Moore, Icarus 99, 261-272 (1992). [2] Elliot et al., Nature 393, 765-767 (1998). [3] Forget, Descamp and Hourdin, in ``Pluto and Triton, comparisons and evolution over time", Lowell Observatory's fourth annual workshop, Flagstaff, Arizona. (1999) [4] Le Guyader, Astron. Astrophys. 272, 687-694 (1993). [5] Kieffer et al., J. Geophys. Res. 105, 9653-9700 (2000).

  9. On the thermal structure of Triton's thermosphere

    NASA Technical Reports Server (NTRS)

    Stevens, Michael H.; Strobel, Darrell F.; Summers, Michael E.; Yelle, Roger V.

    1992-01-01

    The analysis of the Voyager 2 Ultraviolet Spectrometer solar occultation data obtained at Triton is consistent with a spherically symmetric, isothermal thermosphere above 400 km at T(infinity) = 96 K. A detailed calculation of energy loss processes in a pure N2 atmosphere indicates that solar heating, with calculated T(infinity) = 70 K, is insufficient to account for the inferred T(infinity) = 96 K. The magnetosphere must deposit twice as much power as the sun to heat the thermosphere to 96 K and generate the observed N2 tangential column densities above 450 km. The thermal escape of H and N atoms and the downward diffusion of N atoms to recombine below 130 km results in local ionospheric heating efficiency of 24 percent. An upper limit on the tropopause CO mixing ratio of 2 x 10 exp -4 is inferred in the absence of aerosol heating to balance its efficient cooling by LTE rotational line emission.

  10. The Thermal Structure of Triton's Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Strobel, D. F.; Zhu, X.; Stansberry, J. A.; Wasserman, L. H.; Franz, O. G.

    1999-01-01

    The atmospheric structure of Triton in the altitude range 25-150 kilometers shows an unexpectedly steep thermal gradient of 0.26 K per kilometer above 50 kilometer altitude, with a nearly isothermal profile below. The upper part of the profile can be explained by downward conduction of heat deposited by magnetospheric electrons and solar UV. However, the atmospheric temperature below 50 kilometers is too cold for identified radiative processes to dispose of the inferred heat flux (0.0012 erg per square centimeter per second) from the upper atmosphere. This implies that either the atmosphere is not in a steady state and/or an unidentified cooling mechanism is at work in the altitude range 25-50 kilometers. When extrapolated to the surface, the inversion results yield a pressure of 19.0 sup (+1.8) sub (-1.5), mubar, about 5mubar greater than that observed by Voyager.

  11. The Triton: Design concepts and methods

    NASA Technical Reports Server (NTRS)

    Meholic, Greg; Singer, Michael; Vanryn, Percy; Brown, Rhonda; Tella, Gustavo; Harvey, Bob

    1992-01-01

    During the design of the C & P Aerospace Triton, a few problems were encountered that necessitated changes in the configuration. After the initial concept phase, the aspect ratio was increased from 7 to 7.6 to produce a greater lift to drag ratio (L/D = 13) which satisfied the horsepower requirements (118 hp using the Lycoming O-235 engine). The initial concept had a wing planform area of 134 sq. ft. Detailed wing sizing analysis enlarged the planform area to 150 sq. ft., without changing its layout or location. The most significant changes, however, were made just prior to inboard profile design. The fuselage external diameter was reduced from 54 to 50 inches to reduce drag to meet the desired cruise speed of 120 knots. Also, the nose was extended 6 inches to accommodate landing gear placement. Without the extension, the nosewheel received an unacceptable percentage (25 percent) of the landing weight. The final change in the configuration was made in accordance with the stability and control analysis. In order to reduce the static margin from 20 to 13 percent, the horizontal tail area was reduced from 32.02 to 25.0 sq. ft. The Triton meets all the specifications set forth in the design criteria. If time permitted another iteration of the calculations, two significant changes would be made. The vertical stabilizer area would be reduced to decrease the aircraft lateral stability slope since the current value was too high in relation to the directional stability slope. Also, the aileron size would be decreased to reduce the roll rate below the current 106 deg/second. Doing so would allow greater flap area (increasing CL(sub max)) and thus reduce the overall wing area. C & P would also recalculate the horsepower and drag values to further validate the 120 knot cruising speed.

  12. Distribution and nature of UV absorbers on Triton's surface

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1995-01-01

    Substantial evidence suggests that a UV spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAMs exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SaM material. We hope to determine if UV-SAMs on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAMs has been determined, further constraints on their composition cable made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

  13. Distribution and nature of UV absorbers on Triton's surface

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1994-01-01

    Substantial evidence suggests that a UV Spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAM's exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SAM material. We hope to determine if UV-SAM's on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAM's has been determined, further constraints on their composition can be made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on Voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

  14. Lattice physics capabilities of the SCALE code system using TRITON

    SciTech Connect

    DeHart, M. D.

    2006-07-01

    This paper describes ongoing calculations used to validate the TRITON depletion module in SCALE for light water reactor (LWR) fuel lattices. TRITON has been developed to provide improved resolution for lattice physics mixed-oxide fuel assemblies as programs to burn such fuel in the United States begin to come online. Results are provided for coupled TRITON/PARCS analyses of an LWR core in which TRITON was employed for generation of appropriately weighted few-group nodal cross-sectional sets for use in core-level calculations using PARCS. Additional results are provided for code-to-code comparisons for TRITON and a suite of other depletion packages in the modeling of a conceptual next-generation boiling water reactor fuel assembly design. Results indicate that the set of SCALE functional modules used within TRITON provide an accurate means for lattice physics calculations. Because the transport solution within TRITON provides a generalized-geometry capability, this capability is extensible to a wide variety of non-traditional and advanced fuel assembly designs. (authors)

  15. The photochemistry of methane in the atmosphere of Triton

    NASA Technical Reports Server (NTRS)

    Strobel, Darrell F.; Summers, Michael E.; Herbert, Floyd; Sandel, Bill R.

    1990-01-01

    The model of Summers and Strobel (1989) for photochemical reactions in the Uranus atmosphere was modified and used for quantitative calculations of methane in the atmosphere of Triton. The principal adjustable parameters in the new model are the surface CH4 concentrations and the vigor of vertical mixing in Triton's lower atmosphere. It is shown the rate of methane photolysis that was calculated is sufficient to generate a smog of condensed C2H2, C2H4, C2H6, and C4H2 particles in the lowest 30 km of Triton's atmosphere, with an optical depth consistent with the Voyager imaging results.

  16. Voyager radio science observations of Neptune and Triton

    NASA Astrophysics Data System (ADS)

    Tyler, G. L.; Sweetnam, D. N.; Anderson, J. D.; Borutzki, S. E.; Campbell, J. K.; Kursinski, E. R.; Levy, G. S.; Lindal, G. F.; Lyons, J. R.; Wood, G. E.

    1989-12-01

    Voyager 2 undertook radio science investigations of the Neptune and Triton masses and densities, as well as of their atmospheric and ionospheric vertical structures, the atmospheric composition and low-order gravitational harmonics of Neptune, and ring material characteristics. Upon probing the atmosphere of Neptune to a pressure level of about 500,000 Pa, the effects of a methane cloud region and of ammonia absorption below the cloud have become apparent. The tenuous neutral atmosphere of Triton produced distinct signatures in the occultation data; it is inferred that the Triton atmosphere is controlled by water-pressure equilibrium with surface ices.

  17. Method for fabricating uranium foils and uranium alloy foils

    DOEpatents

    Hofman, Gerard L.; Meyer, Mitchell K.; Knighton, Gaven C.; Clark, Curtis R.

    2006-09-05

    A method of producing thin foils of uranium or an alloy. The uranium or alloy is cast as a plate or sheet having a thickness less than about 5 mm and thereafter cold rolled in one or more passes at substantially ambient temperatures until the uranium or alloy thereof is in the shape of a foil having a thickness less than about 1.0 mm. The uranium alloy includes one or more of Zr, Nb, Mo, Cr, Fe, Si, Ni, Cu or Al.

  18. Lithium-6 foil neutron detector

    SciTech Connect

    Young, C.A.

    1982-12-21

    A neutron detection apparatus is provided which includes a selected number of flat surfaces of lithium-6 foil, and which further includes a gas mixture in contact with each of the flat surfaces for selectively reacting to charged particles emitted by or radiated from the lithium foil. A container is provided to seal the lithium foil and the gas mixture in a volume from which water vapor and atmospheric gases are excluded, the container having one or more walls which are transmissive to neutrons. Monitoring equipment in contact with the gas mixture detects reactions taking place in the gas mixture, and, in response to such reactions, provides notice of the flux of neutrons passing through the volume of the detector.

  19. SELECTIVE ABSORBER COATED FOILS FOR SOLAR COLLECTORS

    SciTech Connect

    Lampert, Carl M.

    1980-04-01

    Solar absorber metal foils are discussed in terms of materials and basic processing science. Also included is the use of finished heavy sheet stock for direct fabrication of solar collector panels. Both the adhesives and bonding methods for foils and sheet are surveyed. Developmental and representative commercial foils are used as illustrative examples. As a result it was found that foils can compete economically with batch plating but are limited by adhesive temperature stability. Also absorber foils are very versatile and direct collector fabrication from heavy foils appears very promising.

  20. The Revised Pole Model and New Observations of Triton

    NASA Astrophysics Data System (ADS)

    Zhang, H.-Y.; Shen, K.-X.; Qiao, R.-Ch; Dourneau, G.; Yu, Y.

    2015-10-01

    We used 3108 Earth-based astrometric observations from the Natural Satellite Data Center (NSDC) over more than 30 years time span from 1975 to 2006 for determining the epoch state vectors of the Neptunes largest satellite Triton. In integrating the perturbation equation, the barycentric frame of Neptune-Triton system is adopted, and in considering the oblateness perturbation due to Neptune, a revised pole model describing the precession of the Neptune's pole is used in our calculation. Moreover, a total of 1095 new observed positions of Triton were collected during 46 nights of observations in 2007, 2008 and 2009. We compared our observations to two ephemerides of Triton and most of the available planetary ephemerides of Neptune.

  1. Neutral particle measurements of fusion tritons in JET

    SciTech Connect

    Afanasyev, V. I.; Khudoleev, A. V.

    2010-08-15

    A neutral particle analyzer [A.D. Izvozchikov et al., JET Report No. JET-R(91)-12, 1991] operating in the MeV energy range was used to measure the flux of neutralized d-d fusion tritons emitted from the hot-ion H-mode deuterium plasma heated by deuterium neutral beams. It was found that tritons in the energy range of 0.3-1.1 MeV were largely neutralized by the beam atoms and the beam halo atoms. This enabled us to find the localized energy distribution function of the fusion tritons in the central plasma region. Simulation of the triton energy distribution function shows that MeV ions in the JET hot-ion H-mode plasma behave classically.

  2. Voyager IRIS Measurements of Triton's Thermal Emission: Impllications for Pluto?

    NASA Astrophysics Data System (ADS)

    Stansberry, John A.; Spencer, John; Linscott, Ivan

    2015-11-01

    The New Horizons Pluto encounter data set includes unique observations obtained using the Radio Science experiment to measure the night-side thermal emission at centimeter wavelengths, well beyond the emission peak (in the 70 to 100 micron range). 26 years ago the Voyager 2 Infrared Interferometer Spectrometer (IRIS) obtained spectra in the 30 - 50 micron wavelength range to try and detect thermal emission from Pluto's sibling, Triton. Conrath etal. (1989) analyzed 16 of the IRIS spectra of Triton's dayside and derived a weak limit of 36 K - 41 K. We have analysed those, and an additional 75 spectra, to refine the limits on the temperature of Triton's surface, and to explore diurnal differences in the thermal emission. Triton results from other Voyager instruments provide important constraints on our interpretation of the IRIS data, as do Spitzer measurements of Pluto's thermal emission.For unit-emissivity, average temperature is 34 K, inconsistent with the pressure of Triton's atmosphere (13 - 19 microbar), the presence of beta-phase nitrogen ice on the surface, and the likely presence ofwarm regions on the surface. The atmospheric pressure requires nitrogen ice temperatures of 37.4 K - 38.1 K, which in turn requires emissivity of 0.31--0.53. Such a low emissivity in this spectral region might be expected if the surface is dominated by nitrogen or methane ice. Averages of data subsets show evidence for brightness temperature variations across Triton's surface. Surprisingly, the data seem to indicate that Triton's nightside equatorial region was warmer than on the dayside.These Voyager results for Triton provide a useful context for interpreting New Horizons and ALMA observations of emission from Pluto in the sub-millimeter and centimeter region. JWST will be capable of detecting Triton's and Pluto's 10 - 28 micron thermal emission, although scattered light from Neptune may be an issue for the Triton. Combined with new capabilities of ALMA to measure the sub

  3. Discovery of a Remarkable Opposition Surge on Triton

    NASA Astrophysics Data System (ADS)

    Buratti, B. J.; Bauer, J.; Hicks, M.; Herbert, B.; Schmidt, B.; Cobb, B.; Ward, J.

    2006-05-01

    The large Neptunian satellite Triton is one of three moons in the outer Solar System that exhibit volcanism. Triton's volcanoes appear to be driven by solar heating. In addition, significant seasonal volatile is expected to occur on Triton. To understand the nature and extent of activity on Triton, including volcanism and seasonal volatile transport, we have undertaken a program of deriving the surface properties of Triton through time by means of ground- based observations. Another motivation for our work is to closely study a body that may bear a strong resemblance to the planet Pluto and the swarm of icy bodies in the outer Solar System now known as Kuiper Belt Objects. One important measurement is the solar phase curve, or the brightness as a function of the angle between the observer, the object being observed, and the sun. Most significant are observations at large solar phase angles, which probe the roughness of the surface, and small angles, which characterize the fluffiness of the surface and give clues to optical phenomena such as coherent backscatter. For Triton, large phase angles are not observable from Earth, but the 2004 season presented an opportunity in which the solar phase angle reached the exceedingly low value of 0.002 degrees. During the 2004 season, photometric observations of Triton's phase curve were obtained in the astronomical BVRI filters, spanning wavelengths from 0.45 to 0.89 microns. Triton exhibits a large increase in its brightness as the solar phase angle approaches zero. There is a wavelength dependence to this opposition surge, the term commonly used to describe the non-linear increase in brightness observed on almost all airless bodies.

  4. A structural origin for the cantaloupe terrain of Triton

    NASA Technical Reports Server (NTRS)

    Boyce, Joseph M.

    1993-01-01

    Cantaloupe terrain is unique to Triton. It is Triton's oldest terrain and includes about 250,000 km sq. region displaying sparsely cratered, closely spaced, nearly circular dimples about 30-40 km across. This terrain is found on no other planet because, only on Triton the final major global thermal pulse (1) caused completed (or nearly) interior melting resulting in a cooling history where large thermal stresses shattered and contorted a thin, weak lithosphere, and (2) occurred after heavy bombardment so that the surface features were preserved. The cantaloupe terrain is composed of intersecting sets of structures (folds and/or faults) that have developed as a result of global compression generated by volumetric changes associated with cooling of Triton's interior. Further, it is proposed that these structures developed after the period of heavy bombardment, and resulted from the last major global thermal epoch in Triton's unique history (either caused by tidal or radio metric heating). Initially, as the body cooled and the structures formed, their surface topography was most likely modified by thermal relaxation of the warm surface ices. In other bodies like Mercury, thermal stresses generated from global cooling and contraction have resulted in widely spaced thrust faults, whereas on Triton, thermal stresses produced more closely-spaced folds and faults sets. This difference in structural style is probably due to differences in lithospheric properties (thickness, strength, etc.), the magnitude of stress (directly dependent on the thermal history), and when the structures formed, relative to the period of heavy bombardment.

  5. The BVRI and methane lightcurve of Triton in 2003

    NASA Astrophysics Data System (ADS)

    Schmidt, B.; Herbert, B.; Bauer, J. M.; Hicks, M. D.; Buratti, B. J.; Young, J.

    2003-12-01

    Photometric measurements of Triton in the BVRI and 890 nm filter system were obtained in June, July, and (tentatively) early August 2003. The motivation for these measurements was to confirm the recent observation that the lightcurve of Triton has increased markedly in amplitude (Cobb et al. B.A.A.S 33, 1130 (2001)). If the albedo patterns on Triton remained unchanged since the Voyager encounter in 1989, the current amplitude of Triton's visual lightcurve should be less than 0.05 magnitudes (Hillier et al., JGR 96, 19211). Measurements in 2001 showed an amplitude of nearly 0.20 magnitudes (Cobb et al., op. cit.), indicating volatile transport on the surface. Changes in Triton's color (Hicks et al., 2003, accepted for publication in Icarus), and atmospheric pressure and temperature (Elliot et al., Icarus 148, 347 (2000)) also support the existence of sublimation and possible movement of volatiles and associated changes in albedo patterns. The preliminary analysis of data from the summer of 2003 shows a visual amplitude of 0.17 +/- 0.05 magnitudes, in good agreement with the results from 2001, and far larger than that expected if there were no change in the albedo patterns on Triton's surface. Work carried out at Jet Propulsion Laboratory, California Inst. of Technology, with funding from NASA.

  6. A structural origin for the cantaloupe terrain of Triton

    NASA Astrophysics Data System (ADS)

    Boyce, Joseph M.

    1993-03-01

    Cantaloupe terrain is unique to Triton. It is Triton's oldest terrain and includes about 250,000 km sq. region displaying sparsely cratered, closely spaced, nearly circular dimples about 30-40 km across. This terrain is found on no other planet because, only on Triton the final major global thermal pulse (1) caused completed (or nearly) interior melting resulting in a cooling history where large thermal stresses shattered and contorted a thin, weak lithosphere, and (2) occurred after heavy bombardment so that the surface features were preserved. The cantaloupe terrain is composed of intersecting sets of structures (folds and/or faults) that have developed as a result of global compression generated by volumetric changes associated with cooling of Triton's interior. Further, it is proposed that these structures developed after the period of heavy bombardment, and resulted from the last major global thermal epoch in Triton's unique history (either caused by tidal or radio metric heating). Initially, as the body cooled and the structures formed, their surface topography was most likely modified by thermal relaxation of the warm surface ices. In other bodies like Mercury, thermal stresses generated from global cooling and contraction have resulted in widely spaced thrust faults, whereas on Triton, thermal stresses produced more closely-spaced folds and faults sets. This difference in structural style is probably due to differences in lithospheric properties (thickness, strength, etc.), the magnitude of stress (directly dependent on the thermal history), and when the structures formed, relative to the period of heavy bombardment.

  7. Carbon foils for space plasma instrumentation

    NASA Astrophysics Data System (ADS)

    Allegrini, F.; Ebert, R. W.; Funsten, H. O.

    2016-05-01

    Carbon foils have been successfully used for several decades in space plasma instruments to detect ions and neutral atoms. These instruments take advantage of two properties of the particle-foil interaction: charge conversion of neutral atoms and/or secondary electron emission. This interaction also creates several adverse effects for the projectile exiting the foil, such as angular scattering and energy straggling, which usually act to reduce the sensitivity and overall performance of an instrument. The magnitude of these effects mainly varies with the incident angle, energy, and mass of the incoming projectile and the foil thickness. In this paper, we describe these effects and the properties of the interaction. We also summarize results from recent studies with graphene foils, which can be made thinner than carbon foils due to their superior strength. Graphene foils may soon replace carbon foils in space plasma instruments and open new opportunities for space research in the future.

  8. Force Generation by Flapping Foils

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, P. R.; Donnelly, M.

    1996-11-01

    Aquatic animals like fish use flapping caudal fins to produce axial and cross-stream forces. During WW2, German scientists had built and tested an underwater vehicle powered by similar flapping foils. We have examined the forces produced by a pair of flapping foils. We have examined the forced produced by a pair of flapping foils attached to the tail end of a small axisymmetric cylinder. The foils operate in-phase (called waving), or in anti-phase (called clapping). In a low-speed water tunnel, we have undertaken time-dependent measurements of axial and cross-stream forces and moments that are exerted by the vortex shedding process over the entire body. Phase-matched LDV measurements of vorticity-velocity vectors, as well as limited flow visualization of the periodic vortex shedding process have also been carried out. The direction of the induced velocity within a pair of shed vortices determines the nature of the forces produced, viz., thrust or drag or cross-stream forces. The clapping mode produces a widely dispersed symmetric array of vortices which results in axial forces only (thrust and rag). On the other hand, the vortex array is staggered in the waving mode and cross-stream (maneuvering) forces are then generated.

  9. Passive Thermal Management of Foil Bearings

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J. (Inventor)

    2015-01-01

    Systems and methods for passive thermal management of foil bearing systems are disclosed herein. The flow of the hydrodynamic film across the surface of bearing compliant foils may be disrupted to provide passive cooling and to improve the performance and reliability of the foil bearing system.

  10. Extended foil capacitor with radially spoked electrodes

    DOEpatents

    Foster, James C.

    1990-01-01

    An extended foil capacitor has a conductive disk electrically connected in oncrushing contact to the extended foil. A conductive paste is placed through spaces between radial spokes on the disk to electrically and mechanically connect the extended foil to the disk.

  11. The Origin of the Moon and Triton

    NASA Astrophysics Data System (ADS)

    Johnson, F. M.

    2004-12-01

    In 1879, George Darwin(1) had proposed that the moon originated from a rapidly spinning Earth on which equatorial gravitative attraction was nearly overcome by centrifical force. During a 1964 conference, D.U. Wise(2) and others analyzed this hypothesis in greater detail. However, recent studies warranted a fundamentally new approach with regards to the origin of the solar system. A re-examination of the spin-off (fission) hypothesis of the moon from the earth, using slightly different assumptions than scientists had previously used (allowing for a more extreme version of an expanding earth), provided the earth's original radius (357 km), density (3.13 x 104 g/cc) and spin rate (0.132 radians/sec.). It was found that Neptune underwent a similar development with the fission of Triton. The remarkably large initial densities, of both Earth and Neptune (7.2 x 105 gm/cc) are consistent with the overall theory(3,4) previously discussed regarding the evolution of the solar system from a neutron star type proto-sun's dense core. The primary calculations involve conservation of angular momentum of each of the rotating and revolving planetary systems. (1) Darwin, G. H. Phil. Trans. Roy. Soc. (London) 170, 1 (1879) (2) D.U. Wise, ``The Earth-Moon System" p. 213, Marsden and Cameron Eds. Plenum Press (1966) (3) Fred M. Johnson, ``Voyage Into Astronomy", Kendall/ Hunt Publ., (1977) (4) Fred M. Johnson, Mem. Soc. Roy. des Sciences de Liége, 6th series, vol. III, p. 609-627 (1972).

  12. Historical photometric evidence for volatile migration on Triton

    NASA Technical Reports Server (NTRS)

    Buratti, Bonnie J.; Goguen, Jay D.; Gibson, James; Mosher, Joel

    1994-01-01

    Analysis of CCD images of Triton obtained with the 1.5-m telescope on Palomar Mountain shows that in the time period surrounding the Voyager 2 encounter with the satellite (1985-1990), no changes in the satellite's visual albedo or color occurred. The published observations of Triton in the 0.35- to 0.60-micrometer spectral region obtained between 1950 and 1990 were reanalyzed to detect historical variability in both its albedo and visual color. Analysis of the photometry indicates that there is little, if any, change in Triton's visual geometric albedo. This result is consistent with the albedo pattern observed by Voyager and the change in sub-Earth latitude. Two distinct types of color changes are evident: a significant secular increase in the blue region of the visual spectrum since at least the 1950s, and the reported dramatic reddening of Triton's spectrum in the late 1970s. The latter change can be explained only by a short-lived geological phenomenon. Triton's changing pole orientation with respect to a terrestrial observer cannot explain the secular color changes. These changes imply volatile transport on a global scale on Triton's surface during the past 4 decades. We present two models which show that either removal of a red volatile from Triton's polar cap or deposition of a blue volatile in the equatorial regions can explain the secular color changes. A third possibility is that the changes are the result of the alpha-beta phase transition of nitrogen and subsequent fracturing of the polar cap region (N. S. Duxbury and R. H. Brown (1993).

  13. A model of Triton's role in Neptune's magnetosphere

    NASA Technical Reports Server (NTRS)

    Decker, R. B.; Cheng, A. F.

    1994-01-01

    Escape of neutral hydrogen (H) and nitrogen (N) from Triton's maintains a large neutral cloud, called the Triton torus, in Neptune's magnetosphere. We have developed the first detailed Monte Carlo simulation model of the Triton torus that includes the collisionality, the complex geometry, the injection of two neutral species from Triton (H and N), and the combined effects of photoionization, electron impact ionization, and charge exchange. Ionization in Neptune's plasma sheet was modeled using Voyager plasma observations. Collisions cause both the H and N neutral clouds to become more radially extended, both toward Neptune and out beyond the magnetopause, as well as more extended in latitude, when compared with collisionless models. Moreover, collisions of H with the much more massive N greatly enhance the collisional ejection of H from the system and into Neptune's atmosphere. This effect decreases the probability of H ionization within the magnetosphere relative to that for N, and furthermore causes model results for two-species injection from Triton to differ significantly from those for H injection alone. For a hydrogen escape rate from Triton of 5 x 10(exp 25)/s, as given by photo-chemical models of Triton's upper atmosphere, a nitrogen escape rate of 5 x 10(exp 24)/s gives proton and N(+) sources of 5.6 x 10(exp 24)/s and 3.3 x 10(exp 24)/s, respectively, whose ratio is close to the observed ratio of protons to heavies. A nitrogen escape rate of 2 x 10(exp 25)/s, yields an N(+) source more than twice that of protons, inconsistent with the Voyager data.

  14. Pluto and Triton: Interactions Between Volatiles and Dynamics

    NASA Technical Reports Server (NTRS)

    Rubincam, D. P.

    2001-01-01

    Volatiles moving across the surfaces of Pluto and Triton can give rise to interesting dynamical consequences. Conversely, measurement of dynamical states can help constrain the movement of volatiles and interior structure of both bodies. Polar wander may theoretically occur on both Triton and Pluto. Triton's obliquity is low, so that the equatorial regions receive more insolation than the poles. Hence there is a tendency for nitrogen ice to sublime at the equator and condense at the poles, creating polar caps. If the nitrogen supply is large enough, then these caps could move in approximately 10(exp 5) years the global equivalent of 200 m of ice to the poles. At this point the equatorial moment of inertia becomes larger than the moment of inertia measured about the rotation axis, so that Triton overbalances and becomes dynamically unstable. The satellite then undergoes polar wander, restoring stability when the new equator contains the excess matter. Hence the pole may be continually wandering. Neptune raises a permanent tidal bulge on Triton, so that the satellite's surface is elongated like a football, with the long axis pointing at Neptune. This is expected to be the axis about which the pole wanders. Volatile migration would resurface the satellite to some depth and wandering would disturb leading side/trailing side crater statistics. Additional information is contained in the original extended abstract.

  15. The Surface Compositions of Triton, Pluto, and Charon

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.; Roush, Ted L.; Owen, Tobias C.; Quirico, Eric; DeBergh, Catherine

    1995-01-01

    Neptune's satellite Triton, and the planet-satellite binary Pluto and Charon, are the most distant planetary bodies on which ices have been directly detected. Triton and Pluto have very similar dimensions and mean densities, suggesting a similar or common origin. Through earth-based spectroscopic observations in the near-infrared, solid N2, CH4, and CO have been found on both bodies, with the additional molecule C02 on Triton. N2 dominates both surfaces, although the coverage is not spatially uniform. On Triton, the CH4 and CO are mostly or entirely frozen in the N2 matrix, while CO2 may be spatially segregated. On Pluto, some CH4 and the CO are frozen in the N2 matrix, but there is evidence for additional CH4 in a pure state, perhaps lying as a lag deposit on a subsurface layer of N2. Despite their compositional and dimensional similarities, Pluto and Triton are quite different from one another in detail. Additional hydrocarbons and other volatile ices have been sought spectroscopically but not yet have been detected. The only molecule identified on Pluto's satellite Charon is solid H2O, but the spectroscopic data are of low precision and admit the presence of other ices such as CH4.

  16. Pluto and Triton: Interactions Between Volatiles and Dynamics

    NASA Astrophysics Data System (ADS)

    Rubincam, D. P.

    2001-01-01

    Volatiles moving across the surfaces of Pluto and Triton can give rise to interesting dynamical consequences. Conversely, measurement of dynamical states can help constrain the movement of volatiles and interior structure of both bodies. Polar wander may theoretically occur on both Triton and Pluto. Triton's obliquity is low, so that the equatorial regions receive more insolation than the poles. Hence there is a tendency for nitrogen ice to sublime at the equator and condense at the poles, creating polar caps. If the nitrogen supply is large enough, then these caps could move in approximately 105 years the global equivalent of 200 m of ice to the poles. At this point the equatorial moment of inertia becomes larger than the moment of inertia measured about the rotation axis, so that Triton overbalances and becomes dynamically unstable. The satellite then undergoes polar wander, restoring stability when the new equator contains the excess matter. Hence the pole may be continually wandering. Neptune raises a permanent tidal bulge on Triton, so that the satellite's surface is elongated like a football, with the long axis pointing at Neptune. This is expected to be the axis about which the pole wanders. Volatile migration would resurface the satellite to some depth and wandering would disturb leading side/trailing side crater statistics. Additional information is contained in the original extended abstract.

  17. Hydrothermal processing of cometary volatiles--applications to Triton.

    PubMed

    Shock, E L; McKinnon, W B

    1993-01-01

    Subsequent to its capture by Neptune, Triton could have experienced an episode of tidal heating sufficient to melt its icy mantle and possibly its rocky core as well. This heating would have driven hydrothermal circulation at the core-rock/mantle-ocean boundary. We consider the chemical consequences of this hydrothermal reprocessing on Triton's volatile budget by assuming an initial cometary composition for the icy mantle and evaluating the effects of changes in temperature and oxidation state. We assume that the latter would have been controlled by mineral assemblages in the rock. Such reprocessing could explain the lack of carbon monoxide in the atmosphere of Triton and its depletion relative to N2 and (apparently) CO2 in the satellite's surface ices. Our calculations also show that whatever the original source of nitrogen in Triton, N2 and/or NH3 are likely abundant products of hydrothermal reprocessing. Depending on the temperature and prevailing oxidation state, acetic acid, ethanol, urea, methanol, and ethanamine are possible important components, in addition to ammonia, of the resulting mantle material. Triton may thus preserve the organic chemistry that might have led to the origin of life in early terrestrial hydrothermal systems. PMID:11540242

  18. Triton's Summer Sky of Methane and Carbon Monoxide

    NASA Astrophysics Data System (ADS)

    2010-04-01

    According to the first ever infrared analysis of the atmosphere of Neptune's moon Triton, summer is in full swing in its southern hemisphere. The European observing team used ESO's Very Large Telescope and discovered carbon monoxide and made the first ground-based detection of methane in Triton's thin atmosphere. These observations revealed that the thin atmosphere varies seasonally, thickening when warmed. "We have found real evidence that the Sun still makes its presence felt on Triton, even from so far away. This icy moon actually has seasons just as we do on Earth, but they change far more slowly," says Emmanuel Lellouch, the lead author of the paper reporting these results in Astronomy & Astrophysics. On Triton, where the average surface temperature is about minus 235 degrees Celsius, it is currently summer in the southern hemisphere and winter in the northern. As Triton's southern hemisphere warms up, a thin layer of frozen nitrogen, methane, and carbon monoxide on Triton's surface sublimates into gas, thickening the icy atmosphere as the season progresses during Neptune's 165-year orbit around the Sun. A season on Triton lasts a little over 40 years, and Triton passed the southern summer solstice in 2000. Based on the amount of gas measured, Lellouch and his colleagues estimate that Triton's atmospheric pressure may have risen by a factor of four compared to the measurements made by Voyager 2 in 1989, when it was still spring on the giant moon. The atmospheric pressure on Triton is now between 40 and 65 microbars - 20 000 times less than on Earth. Carbon monoxide was known to be present as ice on the surface, but Lellouch and his team discovered that Triton's upper surface layer is enriched with carbon monoxide ice by about a factor of ten compared to the deeper layers, and that it is this upper "film" that feeds the atmosphere. While the majority of Triton's atmosphere is nitrogen (much like on Earth), the methane in the atmosphere, first detected by

  19. Tidal evolution in the Neptune-Triton system

    NASA Technical Reports Server (NTRS)

    Chyba, C. F.; Jankowski, D. G.; Nicholson, P. D.

    1989-01-01

    Triton, which is currently spiralling toward Neptune due to tides raised on both bodies, possesses an obliquity which may lie close to either a zero-deg 'state 1' or a 100-deg 'state 2' which correspond to the two stable Cassini extrema of its rotational Hamiltonian. The Kaula (1966) tidal formalism is presently used to model the past and future evolution of the system in both states. For nominal parameters in state 1, Triton will reach Neptune's Roche limit in about 3.6 Gyr with a decrease in orbital inclination to 145 deg from the current 159 deg; in the case of state 2, Triton's inclination will increase to 180 deg in 10-100 million years and then transition to state 1, subsequently reaching the Neptune Roche limit in about 1.4 Gyr.

  20. Energy sources for triton's geyser-like plumes

    USGS Publications Warehouse

    Brown, R.H.; Kirk, R.L.; Johnson, T.V.; Soderblom, L.A.

    1990-01-01

    Four geyser-like plumes were discovered near Triton's south pole in areas now in permanent sunlight. Because Triton's southern hemisphere is nearing a maximum summer solstice, insolation as a driver or a trigger for Triton's geyser-like plumes is an attractive hypothesis. Trapping of solar radiation in a translucent, low-conductivity surface layer (in a solid-state greenhouse), which is subsequently released in the form of latent heat of sublimation, could provide the required energy. Both the classical solid-state greenhouse consisting of exponentially absorbed insolation in a gray, translucent layer of solid nitrogen, and the "super" greenhouse consisting of a relatively transparent solid-nitrogen layer over an opaque, absorbing layer are plausible candidates. Geothermal heat may also play a part if assisted by the added energy input of seasonal cycles of insolation.

  1. A thermal model for the seasonal nitrogen cycle on Triton

    NASA Technical Reports Server (NTRS)

    Hansen, Candice J.; Paige, David A.

    1992-01-01

    The seasonal N2-cycle model presently used to characterize such observed phenomena on Triton as atmospheric pressure and surface albedo features at the time of the Voyager encounter incorporates diurnal and seasonal subsurface heat conduction, and can account for the heat capacity of N2 frost deposits. The results obtained by this model differ from those of previous studies in that they do not predict the seasonal freezing-out of the Triton atmosphere; even for a wide range of input parameters, the bright southern polar cap is seen as rather unlikely to be N2. The results support the microphysical arguments for the presence of either dark or smooth translucent N2 frosts on the Triton surface.

  2. Large quasi-circular features beneath frost on Triton

    NASA Technical Reports Server (NTRS)

    Helfenstein, Paul; Veverka, Joseph; Mccarthy, Derek; Lee, Pascal; Hillier, John

    1992-01-01

    Specially processed Voyager 2 images of Neptune's largest moon, Triton, reveal three large quasi-circular features ranging in diameter from 280 to 935 km within Triton's equatorial region. The largest of these features contains a central irregularly shaped area of comparatively low albedo about 380 km in diameter, surrounded by crudely concentric annuli of higher albedo materials. None of the features exhibit significant topographic expression, and all appear to be primarily albedo markings. The features are located within a broad equatorial band of anomalously transparent frost that renders them nearly invisible at the large phase angles (alpha greater than 90 deg) at which Voyager obtained its highest resolution coverage of Triton. The features can be discerned at smaller phase angles (alpha = 66 deg) at which the frost only partially masks underlying albedo contrasts. The origin of the features is uncertain but may have involved regional cryovolcanic activity.

  3. Energy Sources for Triton's Geyser-Like Plumes.

    PubMed

    Brown, R H; Kirk, R L; Johnson, T V; Soderblom, L A

    1990-10-19

    Four geyser-like plumes were discovered near Triton's south pole in areas now in permanent sunlight. Because Triton's southern hemisphere is nearing a maximum summer solstice, insolation as a driver or a trigger for Triton's geyser-like plumes is an attractive hypothesis. Trapping of solar radiation in a translucent, low-conductivity surface layer (in a solid-state greenhouse), which is subsequently released in the form of latent heat of sublimation, could provide the required energy. Both the classical solid-state greenhouse consisting of exponentially absorbed insolation in a gray, translucent layer of solid nitrogen, and the "super" greenhouse consisting of a relatively transparent solid-nitrogen layer over an opaque, absorbing layer are plausible candidates. Geothermal heat may also play a part if assisted by the added energy input of seasonal cycles of insolation. PMID:17793021

  4. Energy sources for Triton's geyser-like plumes

    NASA Technical Reports Server (NTRS)

    Brown, R. H.; Johnson, T. V.; Kirk, R. L.; Soderblom, L. A.

    1990-01-01

    Four geyser-like plumes were discovered near Triton's south pole in areas now in permanent sunlight. Because Triton's southern hemisphere is nearing a maximum summer solstice, insolation as a driver or a trigger for Triton's geyser-like plumes is an attractive hypothesis. Trapping of solar radiation in a translucent, low-conductivity surface layer (in a solid-state greenhouse), which is subsequently released in the form of latent heat of sublimation, could provide the required energy. Both the classical solid-state greenhouse consisting of exponentially absorbed insolation in a gray, translucent layer of solid nitrogen, and the 'super' greenhouse consisting of a relatively transparent solid-nitrogen layer over an opaque, absorbing layer are plausible candidates. Geothermal heat may also play a part if assisted by the added energy input of seasonal cycles of insolation.

  5. Neptune and Triton: A Study in Future Exploration

    NASA Astrophysics Data System (ADS)

    Day, M. D.; Malaska, M. J.; Hosseini, S.; Mcgranaghan, R.; Fernandes, P. A.; Fougere, N.; Clegg, R. N.; Scully, J.; Alibay, F.; Ries, P.; Craig, P. L.; Hutchins, M. L.; Leonard, J.; Uckert, K.; Patthoff, A.; Girazian, Z.

    2013-12-01

    Neptune provides a unique natural laboratory for studying the dynamics of ice giants. Last visited by Voyager 2 in 1989, Neptune and its moon Triton hold important clues to the evolution of the solar system. The Voyager 2 flyby revealed Neptune to be a dynamic world with large storms, unparalleled wind speeds, and an unusual magnetic field. Triton, Neptune's largest satellite, is believed to be a captured Kuiper Belt Object with a thin atmosphere and possible sub-surface ocean. Further study of the farthest planet in our solar system could offer new insights into the dynamics of ice-giant exoplanets, and help us understand their complex atmospheres. The diverse science questions associated with Neptune and Triton motivate the complex and exciting mission proposed in this study. The proposed mission follows the guidelines of the 2013-2022 Planetary Science Decadal Survey, and optimizes the number of high priority science goals achieved, while still maintaining low mission costs. High priority science goals include understanding the structure, composition, and dynamics of Neptune's atmosphere and magnetosphere, as well as analyzing the surface of Triton. With a budget of $1.5 billion, the mission hosts an atmospheric probe and suite of instruments equipped with technologies significantly more advanced than those carried by Voyager 2. Additionally, the mission offers improved spatial coverage and higher resolution measurements than any previously achieved at Neptune. The proposed spacecraft would complete an orbital tour of Neptune and execute several close flybys of Triton. Further study of Neptune and Triton will provide exciting insights into what lies on the edge of our solar system and beyond. This study was prepared in conjunction with Jet Propulsion Laboratory's 2013 Planetary Science Summer School.

  6. Grain metamorphism in polar nitrogen ice on Triton

    NASA Technical Reports Server (NTRS)

    Zent, Aaron P.; Mckay, Christopher P.; Pollack, James B.; Cruikshank, Dale P.

    1989-01-01

    The rate of nitrogen grain growth on putative N2-rich polar caps on Triton is calculated. For most plausible assumptions of independent variables, mean grain sizes in polar N2 are meter-scale. Triton's polar caps should constitute the definitive solar-system test bed for the process of ice grain metamorphism. Interpretation of data already in hand may require long path length through condensed N2, possibly due to grain growth. Upcoming Voyager data may clarify the situation, although possible complications in detecting a glaze of N2 ice exist.

  7. Triton's cratering record and its time of capture

    NASA Technical Reports Server (NTRS)

    Strom, R. G.; Croft, S. K.

    1993-01-01

    Recent impact crater counts on the Voyager 2 high resolution images of Triton have resulted in a more accurate crater size/frequency distribution down to about 3 km diameter. These counts reveal a size/frequency distribution characterized by a differential -4 slope. This is consistent with the observation that there are no craters larger than 27 km diameter on the 20 percent of Triton viewed at resolutions capable of detecting them. A -4 slope is deficient in large craters and at the very low crater density on Triton no craters larger than about 30 km are expected on just 20 percent of the satellite. The Triton size distribution is significantly different from the differential -3 slope of the fresh crater population on Miranda, but both show leading/trailing asymmetries. Since Miranda is in prograde orbit this crater population is probably due to objects in heliocentric orbit, i.e., comets. If this crater population is due to comets, then the significantly different crater population on Triton is probably due to some other population of impacting objects. The most likely origin of these objects is planetesimals in planetocentric orbits. Because Triton is in retrograde orbit, objects in prograde planetocentric orbits will also produce a leading/trailing asymmetry. If the Triton craters are largely the result of objects in planetocentric orbit, then where are the comet craters that should be there if they have a differential -3 distribution function as inferred from the Miranda fresh crater population? The most likely answer is that they are there, but at such a low density that they can not be distinguished from the planetocentric population. An upper bound on this density can be estimated by determining the density of a crater population with a differential -3 slope where no craters larger than 27 km would be expected on the 20 percent of Triton viewed by Voyager at resolutions sufficient to detect them. This density is at the density of the largest crater. At this

  8. Voyager photometry of Triton - Haze and surface photometric properties

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Helfenstein, P.; Verbiscer, A.; Veverka, J.

    1991-01-01

    The Voyager whole-disk observations of Triton at 0.41, 0.48, and 0.56 micron filter wavelengths are analyzed using a model which combines an improved version of Hapke's photometric equation with a thin atmospheric haze layer in the appropriate spherical geometry. The model is shown to describe accurately the phase curves over a range of phase angles and to agree with disk-resolved brightness scans along the photometric equator and mirror meridian. According to the model, the photometric parameters of Triton's regolith are reasonably typical of icy satellites, except for the extremely high (close to unity) single-scattering albedo.

  9. Triton's Summer Sky of Methane and Carbon Monoxide

    NASA Astrophysics Data System (ADS)

    2010-04-01

    According to the first ever infrared analysis of the atmosphere of Neptune's moon Triton, summer is in full swing in its southern hemisphere. The European observing team used ESO's Very Large Telescope and discovered carbon monoxide and made the first ground-based detection of methane in Triton's thin atmosphere. These observations revealed that the thin atmosphere varies seasonally, thickening when warmed. "We have found real evidence that the Sun still makes its presence felt on Triton, even from so far away. This icy moon actually has seasons just as we do on Earth, but they change far more slowly," says Emmanuel Lellouch, the lead author of the paper reporting these results in Astronomy & Astrophysics. On Triton, where the average surface temperature is about minus 235 degrees Celsius, it is currently summer in the southern hemisphere and winter in the northern. As Triton's southern hemisphere warms up, a thin layer of frozen nitrogen, methane, and carbon monoxide on Triton's surface sublimates into gas, thickening the icy atmosphere as the season progresses during Neptune's 165-year orbit around the Sun. A season on Triton lasts a little over 40 years, and Triton passed the southern summer solstice in 2000. Based on the amount of gas measured, Lellouch and his colleagues estimate that Triton's atmospheric pressure may have risen by a factor of four compared to the measurements made by Voyager 2 in 1989, when it was still spring on the giant moon. The atmospheric pressure on Triton is now between 40 and 65 microbars - 20 000 times less than on Earth. Carbon monoxide was known to be present as ice on the surface, but Lellouch and his team discovered that Triton's upper surface layer is enriched with carbon monoxide ice by about a factor of ten compared to the deeper layers, and that it is this upper "film" that feeds the atmosphere. While the majority of Triton's atmosphere is nitrogen (much like on Earth), the methane in the atmosphere, first detected by

  10. Photochemistry of Triton's Atmosphere and Ionosphere

    NASA Technical Reports Server (NTRS)

    Krasnopolsky, Vladimir A.; Cruikshank, Dale P.

    1995-01-01

    The photochemistry of 32 neutral and 21 ion species in Triton's atmosphere is considered. Parent species N2, CH4, and CO (with a mixing ratio of 3 x 10(exp -4) in our basic model) sublime from the ice with rates of 40, 208, and 0.3 g/sq cm/b.y., respectively. Chemistry below 50 km is driven mostly by photolysis of methane by the solar and interstellar medium Lyman-alpha photons, producing hydrocarbons C2H4, C2H6, and C2H2 which form haze particles with precipitation rates of 135, 28, and 1.3 g/sq cm/b.y., respectively. Some processes are discussed which increase the production of HCN (by an order of magnitude to a value of 29 g/sq cm/b.y.) and involve indirect photolysis of N2 by neutrals. Reanalysis of the measured methane profiles gives an eddy diffusion coefficient K = 4 x 10(exp 3)sq cm/s above the tropopause and a more accurate methane number density near the surface, (3.1 +/- 0.8)x IO(exp 11)/cu cm. Chemistry above 200 km is driven by the solar EUV radiation (lambda less than 1000 A) and by precipitation of magnetospheric electrons with a total energy input of 10(exp 8) W (based on thermal balance calculations). The most abundant photochemical species are N, H2, H, 0, and C. They escape with the total rates of 7.7 x 10(exp 24)/ s, 4.5 x 10(exp 25)/s, 2.4 x 10(exp 25)/s, 4.4 x 10(exp 22)/s, and 1.1 x 10(exp 24), respectively. Atomic species are transported to a region of 50-200 km and drive the chemistry there. Ionospheric chemistry explains the formation of an E region at 150-240 km with HCO(+) as a major ion, and of an F region above 240 km with a peak at 320 km and C(+) as a major ion. The ionosphere above 500 km consists of almost equal densities of C(+) and N(+) ions. The model profiles agree with the measured atomic nitrogen and electron density profiles. A number of other models with varying rate coefficients of some reactions, differing properties of the haze particles (chemically passive or active), etc., were developed. These models show that there

  11. Photochemistry of Triton's Atmosphere and Ionosphere

    NASA Technical Reports Server (NTRS)

    Krasnopolsky, Vladimir A.; Cruikshank, Dale P.

    1995-01-01

    The photochemistry of 32 neutral and 21 ion species in Triton's atmosphere is considered. Parent species N2, CH4, and CO (with a mixing ratio of 3 x 10(exp -4) in our basic model) sublime from the ice with rates of 40, 208, and 0.3 g/sq cm/b.y., respectively. Chemistry below 50 km is driven mostly by photolysis of methane by the solar and interstellar medium Lyman-alpha photons, producing hydrocarbons C2H4, C2H6, and C2H2 which form haze particles with precipitation rates of 135, 28, and 1.3 g/sq cm/b.y., respectively. Some processes are discussed which increase the production of HCN (by an order of magnitude to a value of 29 g/sq cm/b.y.) and involve indirect photolysis of N2 by neutrals. Reanalysis of the measured methane profiles gives an eddy diffusion coefficient K = 4 x 10(exp 3) sq cm/s above the tropopause and a more accurate methane number density near the surface, (3.1 +/- 0.8) x 10(exp 11)/cc cm. Chemistry above 200 km is driven by the solar EUV radiation (lambda less than 1000 A)) and by precipitation of magnetospheric electrons with a total energy input of 10(exp 8) W (based on thermal balance calculations). The most abundant photochemical species are N, H2, H, O, and C. They escape with the total rates of 7.7 x 10(exp 24)/ s, 4.5 x 10(exp 25)/ s, 2.4 x 10(exp 25)/ s, 4.4 x 10(exp 22)/ s, and 1.1 x 10(exp 24)/ s, respectively. Atomic species are transported to a region of 50-200 km and drive the chemistry there. Iono- spheric chemistry explains the formation of an E region at 150-240 km with HCO(+) as a major ion, and of an F region above 240 km with a peak at 320 km and C(+) as a major ion. The ionosphere above 500 km consists of almost equal densities of C(+) and N(+) ions. The model profiles agree with the measured atomic nitrogen and electron density profiles. A number of other models with varying rate coefficients of some reactions, differing properties of the haze particles (chemically passive or active), etc., were developed. These models show

  12. Photochemistry of Triton's atmosphere and ionosphere

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.; Cruikshank, Dale P.

    The photochemistry of 32 neutral and 21 ion species in Triton's atmosphere is considered. Parent species N2, CH4, and CO (with a mixing ratio of 3×10-4 in our basic model) sublime from the ice with rates of 40, 208, and 0.3 g/cm2/b.y., respectively. Chemistry below 50 km is driven mostly by photolysis of methane by the solar and interstellar medium Lyman-alpha photons, producing hydrocarbons C2H4, C2H6, and C2H2 which form haze particles with precipitation rates of 135, 28, and 1.3 g/cm2/b.y., respectively. Some processes are discussed which increase the production of HCN (by an order of magnitude to a value of 29 g/cm2/b.y.) and involve indirect photolysis of N2 by neutrals. Reanalysis of the measured methane profiles gives an eddy diffusion coefficient K=4×103 cm2/s above the tropopause and a more accurate methane number density near the surface, (3.1+/-0.8)×1011 cm-3. Chemistry above 200 km is driven by the solar EUV radiation (λ<1000 Å) and by precipitation of magnetospheric electrons with a total energy input of 108 W (based on thermal balance calculations). The most abundant photochemical species are N, N2, H, O, and C. They escape with the total rates of 7.7×1024 s-1, 4.5×1025 s-1, 2.4×1025 s-1, 4.4×1022 s-1, and 1.1×1024 s-1, respectively. Atomic species are transported to a region of 50-200 km and drive the chemistry there. Ionospheric chemistry explains the formation of an E region at 150-240 km with HCO+ as a major ion, and of an F region above 240 km with a peak at 320 km and C+ as a major ion. The ionosphere above 500 km consists of almost equal densities of C+ and N+ ions. The model profiles agree with the measured atomic nitrogen and electron density profiles. A number of other models with varying rate coefficients of some reactions, differing properties of the haze particles (chemically passive or active), etc., were developed. These models show that there are four basic unknown values which have strong impacts on the composition and

  13. Photochemistry of Triton's Atmosphere and Ionosphere

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.; Cruikshank, Dale P.

    1995-10-01

    The photochemistry of 32 neutral and 21 ion species in Triton's atmosphere is considered. Parent species N2, CH4, and CO (with a mixing ratio of 3 x 10-4 in our basic model) sublime from the ice with rates of 40, 208, and 0.3 g/sq cm/b.y., respectively. Chemistry below 50 km is driven mostly by photolysis of methane by the solar and interstellar medium Lyman-alpha photons, producing hydrocarbons C2H4, C2H6, and C2H2 which form haze particles with precipitation rates of 135, 28, and 1.3 g/sq cm/b.y., respectively. Some processes are discussed which increase the production of HCN (by an order of magnitude to a value of 29 g/sq cm/b.y.) and involve indirect photolysis of N2 by neutrals. Reanalysis of the measured methane profiles gives an eddy diffusion coefficient K = 4 x 103sq cm/s above the tropopause and a more accurate methane number density near the surface, (3.1 +/- 0.8)x IO11/cu cm. Chemistry above 200 km is driven by the solar EUV radiation (lambda less than 1000 A) and by precipitation of magnetospheric electrons with a total energy input of 108 W (based on thermal balance calculations). The most abundant photochemical species are N, H2, H, 0, and C. They escape with the total rates of 7.7 x 1024/ s, 4.5 x 1025/s, 2.4 x 1025/s, 4.4 x 1022/s, and 1.1 x 1024, respectively. Atomic species are transported to a region of 50-200 km and drive the chemistry there. Ionospheric chemistry explains the formation of an E region at 150-240 km with HCO(+) as a major ion, and of an F region above 240 km with a peak at 320 km and C(+) as a major ion. The ionosphere above 500 km consists of almost equal densities of C(+) and N(+) ions. The model profiles agree with the measured atomic nitrogen and electron density profiles. A number of other models with varying rate coefficients of some reactions, differing properties of the haze particles (chemically passive or active), etc., were developed. These models show that there are four basic unknown values which have strong impacts

  14. Photochemistry of Triton's atmosphere and ionosphere.

    PubMed

    Krasnopolsky, V A; Cruikshank, D P

    1995-10-25

    The photochemistry of 32 neutral and 21 ion species in Triton's atmosphere is considered. Parent species N2, CH4, and CO (with a mixing ratio of 3 x 10(-4) in our basic model) sublime from the ice with rates of 40, 208, and 0.3 g/cm2/b.y., respectively. Chemistry below 50 km is driven mostly by photolysis of methane by the solar and interstellar medium Lyman-alpha photons, producing hydrocarbons C2H4, C2H6, and C2H2 which form haze particles with precipitation rates of 135, 28, and 1.3 g/cm2/b.y., respectively. Some processes are discussed which increase the production of HCN (by an order of magnitude to a value of 29 g/cm2/b.y.) and involve indirect photolysis of N2 by neutrals. Reanalysis of the measured methane profiles gives an eddy diffusion coefficient K = 4 x 10(3) cm2/s above the tropopause and a more accurate methane number density near the surface, (3.1 +/- 0.8) x 10(11) cm-3. Chemistry above 200 km is driven by the solar EUV radiation (lambda < 1000 angstroms) and by precipitation of magnetospheric electrons with a total energy input of 10(8) W (based on thermal balance calculations). The most abundant photochemical species are N, H2, H, O, and C. They escape with the total rates of 7.7 x 10(24) s-1, 4.5 x 10(25) s-1, 2.4 x 10(25) s-1, 4.4 x 10(22) s-1, and 1.1 x 10(24) s-1, respectively. Atomic species are transported to a region of 50-200 km and drive the chemistry there. Ionospheric chemistry explains the formation of an E region at 150-240 km with HCO+ as a major ion, and of an F region above 240 km with a peak at 320 km and C+ as a major ion. The ionosphere above 500 km consists of almost equal densities of C+ and N+ ions. The model profiles agree with the measured atomic nitrogen and electron density profiles. A number of other models with varying rate coefficients of some reactions, differing properties of the haze particles (chemically passive or active), etc., were developed. These models show that there are four basic unknown values which have

  15. Foil support structure for large electron guns

    SciTech Connect

    Brucker, J.P.; Rose, E.A.

    1993-08-01

    This paper describes a novel support structure for a vacuum diode used to pump a gaseous laser with an electron beam. Conventional support structures are designed to hold a foil flat and rigid. This new structure takes advantage of the significantly greater strength of metals in pure tension, utilizing curved shapes for both foil and support structure. The shape of the foil is comparable to the skin of a balloon, and the shape of the support structures is comparable to the cables of a suspension bridge. This design allows a significant reduction in foil thickness and support structure mass, resulting in a lower electron-beam loss between diode and laser gas. In addition, the foil is pre-formed in the support structure at pressures higher than operating pressure. Therefore, the foil is operated far from the yield point. Increased reliability is anticipated.

  16. Efficiency and lifetime of carbon foils

    SciTech Connect

    Chou, W.; Kostin, M.; Tang, Z.; /Fermilab

    2006-11-01

    Charge-exchange injection by means of carbon foils is a widely used method in accelerators. This paper discusses two critical issues concerning the use of carbon foils: efficiency and lifetime. An energy scaling of stripping efficiency was suggested and compared with measurements. Several factors that determine the foil lifetime--energy deposition, heating, stress and buckling--were studied by using the simulation codes MARS and ANSYS.

  17. The Impact of Developmental Education at Triton College.

    ERIC Educational Resources Information Center

    Chand, Sunil

    1985-01-01

    Describes the following aspects of the Developmental Education Program at Triton College: student placement, courses, faculty selection, reading and writing instruction, mathematics instruction, the Learning Assistance Center (LAC), LAC tutoring, LAC special projects, LAC management, special needs assistance program for disabled students, and…

  18. Triton College: A Review of the Student Personnel Program.

    ERIC Educational Resources Information Center

    Beyerl, Merrill C.; And Others

    This report presents the findings and recommendations of a review of the student personnel services program at Triton College (Illinois), conducted by a team from the Consulting Service of the American Association of State Colleges and Universities. The report briefly describes the college and its administration and suggests a reorganization of…

  19. Wave Features of the Neptune's Satellites: Triton, Proteus, Nereid

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2014-07-01

    Fastly orbiting Triton shows Mars-like tectonic dichotomy and very fine granulation 18 km across. Observed Proteus' granules are due to wave modulation. Nereid's fr.is close to that of Earth, thus their relatively sized granules are quite similar.

  20. Technical Development Path for Foil Gas Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2008-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  1. Free Surface and Flapping Foil Interactions

    NASA Astrophysics Data System (ADS)

    Ananthakrishnan, Palaniswamy

    2014-11-01

    Flapping foils for station-keeping of a near-surface body in a current is analyzed using a finite-difference method based on boundary-fitted coordinates. The foils are hinge-connected to the aft of the body and subject to pitch oscillation. Results are obtained for a range of Strouhal number, Froude number, unsteady frequency parameter τ, Reynolds number and the depth of foil submergence. Results show that at low Strouhal number (St < 0 . 1) and sub-critical unsteady parameter τ < 0 . 25 , the flapping generates drag instead of thrust. At high Strouhal number and super-critical value of the unsteady parameter (τ > 0 . 25) flapping generates high thrust with low efficiency. Thrust and efficiency are found to decrease with decreasing submergence depth of the foil. At the critical τ = 0 . 25 and shallow submergence of the foil, the standing wave generated above the foil continues to grow until breaking; both the thrust and efficiency of the foil are reduced at the critical τ. The necessary conditions for optimal thrust generation by a flapping foil underneath the free surface are found to be (i) Strouhal number in the range from 0.25 to 0.35, (ii) unsteady parameter τ > 0 . 25 and (iii) the maximum angle of attack less than 15° for the flat-plate foil. Supported by the US Office of Naval Research through the Naval Engineering Education Center (NEEC) Consortium of the University of Michigan, Ann Arbor.

  2. On the surface composition of Triton's southern latitudes

    NASA Astrophysics Data System (ADS)

    Holler, B. J.; Young, L. A.; Grundy, W. M.; Olkin, C. B.

    2016-03-01

    We present the results of an investigation to determine the longitudinal (zonal) distributions and temporal evolution of ices on the surface of Triton. Between 2002 and 2014, we obtained 63 nights of near-infrared (0.67-2.55 μ m) spectra using the SpeX instrument at NASA's Infrared Telescope Facility (IRTF). Triton has spectral features in this wavelength region from N2, CO, CH4, CO2, and H2O. Absorption features of ethane (C2H6) and 13CO are coincident at 2.405 μ m, a feature that we detect in our spectra. We calculated the integrated band area (or fractional band depth in the case of H2O) in each nightly average spectrum, constructed longitudinal distributions, and quantified temporal evolution for each of the chosen absorption bands. The volatile ices (N2, CO, CH4) show significant variability over one Triton rotation and have well-constrained longitudes of peak absorption. The non-volatile ices (CO2, H2O) show poorly-constrained peak longitudes and little variability. The longitudinal distribution of the 2.405 μ m band shows little variability over one Triton rotation and is 97 ± 44 ° and 92 ± 44 ° out of phase with the 1.58 μ m and 2.35 μ m CO bands, respectively. This evidence indicates that the 2.405 μ m band is due to absorption from non-volatile ethane. CH4 absorption increased over the period of the observations while absorption from all other ices showed no statistically significant change. We conclude from these results that the southern latitudes of Triton are currently dominated by non-volatile ices and as the sub-solar latitude migrates northwards, a larger quantity of volatile ice is coming into view.

  3. A TENTATIVE IDENTIFICATION OF HCN ICE ON TRITON

    SciTech Connect

    Burgdorf, M.; Cruikshank, D. P.; Dalle Ore, C. M.; Sekiguchi, T.; Nakamura, R.; Orton, G.; Quirico, E.; Schmitt, B.

    2010-08-01

    Spectra of Triton between 1.8 and 5.5 {mu}m, obtained in 2007 May and 2009 November, have been analyzed to determine the global surface composition. The spectra were acquired with the grism and the prism of the Infrared Camera on board AKARI with spectral resolutions of 135 and 22, respectively. The data from 4 to 5 {mu}m are shown in this Letter and compared to the spectra of N{sub 2}, CO, and CO{sub 2}, i.e., all the known ices on this moon that have distinct bands in this previously unexplored wavelength range. We report the detection of a 4{sigma} absorption band at 4.76 {mu}m (2101 cm{sup -1}), which we attribute tentatively to the presence of solid HCN. This is the sixth ice to be identified on Triton and an expected component of its surface because it is a precipitating photochemical product of Triton's thin N{sub 2} and CH{sub 4} atmosphere. It is also formed directly by irradiation of mixtures of N{sub 2} and CH{sub 4} ices. Here we consider only pure HCN, although it might be dissolved in N{sub 2} on the surface of Triton because of the evaporation and recondensation of N{sub 2} over its seasonal cycle. The AKARI spectrum of Triton also covers the wavelengths of the fundamental (1-0) band of {beta}-phase N{sub 2} ice (4.296 {mu}m, 2328 cm{sup -1}), which has never been detected in an astronomical body before, and whose presence is consistent with the overtone (2-0) band previously reported. Fundamental bands of CO and CO{sub 2} ices are also present.

  4. Foil bearing lubrication theory including compressibility effects

    NASA Technical Reports Server (NTRS)

    Gorla, Rama Subba Reddy; Catalano, Daniel A.

    1987-01-01

    An analysis is presented to determine the film thickness in a foil bearing. Using the Reynolds equation and including the compressibility effects of the gas, an equation was developed applicable to the film thickness in a foil bearing. The bearing was divided into three regions, namely, the entrance region, middle region and exit region. Solutions are obtained for the film thickness in each region.

  5. Chromic acid anodizing of aluminum foil

    NASA Technical Reports Server (NTRS)

    Dursch, H.

    1988-01-01

    The success of the Space Station graphite/epoxy truss structure depends on its ability to endure long-term exposure to the LEO environment, primarily the effects of atomic oxygen and the temperture cycling resulting from the 94 minute orbit. This report describes the development and evaluation of chromic acid anodized (CAA) aluminum foil as protective coatings for these composite tubes. Included are: development of solar absorptance and thermal emittance properties required of Al foil and development of CAA parameters to achieve these optical properties; developing techniques to CAA 25 ft lengths of Al foil; developing bonding processes for wrapping the Al foil to graphite/epoxy tubes; and atomic oxygen testing of the CAA Al foil. Two specifications were developed and are included in the report: Chromic Acid Anodizing of Aluminum Foil Process Specification and Bonding of Anodized Aluminum Foil to Graphite/Epoxy Tubes. Results show that CAA Al foil provides and excellent protective and thermal control coating for the Space Station truss structure.

  6. Hot foil transducer skin friction sensor

    NASA Technical Reports Server (NTRS)

    Vranas, T. (Inventor)

    1982-01-01

    The device utilizes foil transducers with only one edge exposed to the fluid flow. The surfaces are polished producing a foil transducer that does not generate turbulence while sufficiently thick to carry the required electrical current for high temperature fluid flow. The assembly utilizes a precut layered metal sandwich with attached electrodes eliminating a need for welding and individual sensor calibration.

  7. Barrier Foil Heating Simulations Using LASNEX

    SciTech Connect

    Ho, D D

    2002-03-12

    It is necessary to place a barrier foil in front of the X-ray converter target to prevent the backstreaming ions. This research note presents the simulations of foil heating using the latest EOS tables. LASNEX simulations are carried out using both DARHT-II and ETA-II beam parameters. Results for all the foils studied here, using the DARHT-II beam parameters, show that the integrated line density along the axis at the end of the 4th pulse remains essentially unchanged even if the foils are heated by beams with relatively small beam spot sizes. The temperature can reach up to 3000 C on graphite foil but can only reach several hundred degree Celsius on Mylar foil. Simulations also show that ETA-II beam can create a ''burn-through'' hole on all the foils except graphite and diamond foils, which may require pre-heat. The threshold beam spot size required for hole formation will be compared with LASNEX simulation for the purpose of code verification.

  8. Nuclear Propulsion using Thin Foiled Fuel

    NASA Astrophysics Data System (ADS)

    Takahashi, H.

    1998-11-01

    A new way to produce plasma for nuclear propulsion is proposed. A thin foiled fuel can be used for converting fission energy to propulsion energy efficiently. The fission products coming out of the thin foil directly ionize the hydrogen molecules which are used for propulsion. Thus very small portion of fission energy deposited in the thin foil, and integrity of the thin foiled fuel can be maintained even in high nuclear power. Fuel material with large thermal fission cross-section is preferable to make thin foiled fuel and the heat deposition in the foil can be reduced. To get high power from the foiled fuel assembly, thermal neutrons which are created out from the assembly can be supplied, or the assembly itself can create the high intensity thermal neutrons by self-multiplication. A flexible design of a highly efficient nuclear propulsion system can be made. The thickness of the foil and the maintenance of the thermo-mechanical integrity can be determined from the fission cross-section and the slowing down power for fission products. The talk discusses the issues related to heat removal from the assembly.

  9. Polar Wander on Triton and Pluto Due to Volatile Migration

    NASA Technical Reports Server (NTRS)

    Rubincam, David Parry

    2002-01-01

    Polar wander may occur on Triton and Pluto because of volatile migration. Triton, with its low obliquity, can theoretically sublimate volatiles (mostly nitrogen) at the rate of approximately 10(exp 14) kilograms per year from the equatorial regions and deposit them at the poles. Assuming Triton to be rigid on the sublimation timescale, after approximately 10(exp 5) years the polar caps would become large enough to cancel the rotational flattening, with a total mass equivalent to a global layer approximately 120-250 m in depth. At this point the pole wanders about the tidal bulge axis, which is the line joining Triton and Neptune. Rotation about the bulge axis might be expected to disturb the leading side/trailing side cratering statistics. Because no such disturbance is observed, it may be that Triton's mantle viscosity is too high but its surface volatile inventory is too low to permit wander. On the other hand, its mantle viscosity might be low, so that any uncompensated cap load might be expected to wander toward the tidal bulge axis. In this case, the axis of wander passes through the equator from the leading side to the trailing side; rotation about this wander axis would not disturb the cratering statistics. Low-viscosity polar wander may explain the bright southern hemisphere: this is the pole which is wandering toward the equator. In any case the permanent polar caps may be geologically very young. Polar wander may possibly take place on Pluto, due to its obliquity oscillations and perihelion-pole geometry. However, Pluto is probably not experiencing any wander at present. The Sun has been shining strongly on the poles over the last half of the obliquity cycle, so that volatiles should migrate to the equator, stabilizing the planet against wander. Spacecraft missions to Triton and Pluto which measure the dynamical flattening could give information about the accumulation of volatiles at the poles. Such information is best obtained by measuring gravity and

  10. A Preliminary Foil Gas Bearing Performance Map

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Radil, Kevin C.; Bruckner, Robert J.; Howard, S. Adam

    2006-01-01

    Recent breakthrough improvements in foil gas bearing load capacity, high temperature tribological coatings and computer based modeling have enabled the development of increasingly larger and more advanced Oil-Free Turbomachinery systems. Successful integration of foil gas bearings into turbomachinery requires a step wise approach that includes conceptual design and feasibility studies, bearing testing, and rotor testing prior to full scale system level demonstrations. Unfortunately, the current level of understanding of foil gas bearings and especially their tribological behavior is often insufficient to avoid developmental problems thereby hampering commercialization of new applications. In this paper, a new approach loosely based upon accepted hydrodynamic theory, is developed which results in a "Foil Gas Bearing Performance Map" to guide the integration process. This performance map, which resembles a Stribeck curve for bearing friction, is useful in describing bearing operating regimes, performance safety margins, the effects of load on performance and limiting factors for foil gas bearings.

  11. Charge-exchange reactions with a radioactive triton beam

    SciTech Connect

    Jaenecke, J.

    1998-12-21

    A high-resolution (t, {sup 3}He) test experiment has been performed recently by making use of a secondary triton beam produced by fragmentation of {alpha}-particles. The purpose of this charge-exchange experiment was to achieve good energy resolution in an (n,p)-type reaction at intermediate bombarding energies. The experiment was carried out with the K1200 cyclotron at the National Superconducting Cyclotron Laboratory using the A1200 beam-analysis system and the S800 magnetic spectrometer. The beam-analysis system was used to transport the energy-dispersed radioactive triton beam from the production target to the target position, and the magnetic spectrometer was used to focus the dispersion-matched {sup 3}He particles from the (t, {sup 3}He) reaction at 0 degree sign onto the focal plane of the spectrometer. An energy resolution of 200-250 keV was achieved.

  12. Nitrogen airglow sources - Comparison of Triton, Titan, and earth

    NASA Technical Reports Server (NTRS)

    Strobel, Darrell F.; Meier, R. R.; Summers, Michael E.; Strickland, Douglas J.

    1991-01-01

    The individual contributions of direct solar excitation, photoelectron excitation, and magnetospheric electron excitation of Triton and Titan airglow observed by the Voyager Ultraviolet Spectrometer (UVS) are quantified. The principal spectral features of Triton's airglow are shown to be consistent with precipitation of magnetospheric electrons with power dissipation about 500 million W. Solar excitation rates of the dominant N2 and N(+) emission features are factors of 2-7 weaker than magnetospheric electron excitation. On Titan, the calculated disk center and bright limb N(+) 1085 A intensities due to solar excitation agree with observed values, while the 970 A feature is mostly N21 c5 band emission. The calculated LBH intensity by photoelectrons suggests that magnetospheric electrons play a minor role in Titan's UV airglow. On earth, solar/photoelectron excitation explains the observed N(+) 1085 A and LBH intensites and accounts for only 40 percent of the N(+) 916 A intensity.

  13. Triton and Nereid astrographic observations from Voyager 2

    NASA Technical Reports Server (NTRS)

    Jacobson, R. A.

    1991-01-01

    This article describes the reduced astrographic observations of Triton and Nereid derived from Voyager 2 imaging data. The data set contains 496 sets of spacecraft-centered fight ascension and declination observations and includes all of the observations used in Voyager encounter operations. The details of the conversion process from imaging to astrographic observations are given. The effect of using the astrographic rather than imaging form in ephemeris improvement is evaluated.

  14. A NEPtune/Triton Vision Mission Using Nuclear Electric Propulsion

    NASA Astrophysics Data System (ADS)

    Bienstock, B.; Atkinson, D. H.; Baines, K.; Mahaffy, P.; Atreya, S.; Stern, A.; Steffes, P.; Wright, M.; Ball Collaboration; Boeing Collaboration

    2005-08-01

    The giant planets of the outer solar system divide into two distinct classes: the ``Gas Giants" Jupiter and Saturn, and the ``Ice Giants" Uranus and Neptune. While the Gas Giants primarily comprise hydrogen and helium, the Ice Giants appear fundamentally different, containing significant amounts of the heavier elements including oxygen, nitrogen, carbon, and sulfur. Comparisons of the internal structure and overall composition of the Gas and Ice Giants will yield valuable insights into the processes that formed our solar system and possibly extrasolar systems. By 2012 detailed studies of the chemical and physical properties of Jupiter and Saturn will have been completed by the Pioneer, Voyager, Galileo, Cassini, and Juno missions. A Neptune Orbiter with Probes mission would deliver the corresponding key data for an Ice Giant. Such a mission to study Triton, Nereid, the other icy satellites of Neptune, Neptune's system of rings, and the deep Neptune atmosphere to pressures ranging from several hundred bars to possibly several kilobars has been studied. Power and propulsion would be provided using nuclear electric propulsion (NEP) technologies. This ambitious mission requires a number of technical issues be investigated and resolved, including: (1) developing a reasonable mission design that allows proper targeting and timing of the entry probe(s) while offering adequate opportunities for Triton, small icy satellite, and ring science, (2) giant-planet atmospheric probe thermal protection system (TPS) design, (3) deep probe design including pressure vessel, seals, windows, penetrations and inlets, (4) deep probe telecommunications through Neptune's dense and absorbing atmosphere, 5) Triton lander design to conduct extended surface science, and (6) defining an appropriate suite of science instruments for the Orbiter, Probes and Landers to explore the depths of the Neptune atmosphere, magnetic field, Triton, and the icy satellites utilizing the ample mass and power

  15. Neptune's Triton: A moon rich in dry ice and carbon

    SciTech Connect

    Prentice, A.J.R.

    1989-08-01

    The encounter of the spacecraft Voyager 2 with Neptune and its large satellite Triton in August 1989 will provide a crucial test of ideas regarding the origin and chemical composition of the outer solar system. In this pre-encounter publication, the possibility is quantified that Titron is a captured moon which, like Pluto and Charon, originally condensed as a major planetesimal within the gas ring that was shed by the contracting protosolar cloud at Neptune's orbit. Ideas of supersonic convective turbulence are used to compute the gas pressure, temperature and rat of catalytic synthesis of CH{sub 4}, CO{sub 2}, and C(s) within the protosolar cloud, assuming that all C is initially present as CO. The calculations lead to a unique composition for Triton, Pluto, Charon: each body consists of, by mass, 18 1/2% solid CO{sub 2} ice, 4 percent graphite, 1/2% CH{sub 4} ice, 29 percent methanated water ice and 48 percent of anhydrous rock. This mix has a density consistent with that of the Pluto-Charon system and yields a predicted mean density for Triton of 2.20 + or - 0.5 g/cu cm, for satellite radius equal to 1,750 km.

  16. Neptune's Triton: A moon rich in dry ice and carbon

    NASA Technical Reports Server (NTRS)

    Prentice, A. J. R.

    1989-01-01

    The encounter of the spacecraft Voyager 2 with Neptune and its large satellite Triton in August 1989 will provide a crucial test of ideas regarding the origin and chemical composition of the outer solar system. In this pre-encounter publication, the possibility is quantified that Titron is a captured moon which, like Pluto and Charon, originally condensed as a major planetesimal within the gas ring that was shed by the contracting protosolar cloud at Neptune's orbit. Ideas of supersonic convective turbulence are used to compute the gas pressure, temperature and rat of catalytic synthesis of CH4, CO2, and C(s) within the protosolar cloud, assuming that all C is initially present as CO. The calculations lead to a unique composition for Triton, Pluto, Charon: each body consists of, by mass, 18 1/2 percent solid CO2 ice, 4 percent graphite, 1/2 percent CH4 ice, 29 percent methanated water ice and 48 percent of anhydrous rock. This mix has a density consistent with that of the Pluto-Charon system and yields a predicted mean density for Triton of 2.20 + or - 0.5 g/cu cm, for satellite radius equal to 1,750 km.

  17. Triton memory time in solid DT and its nuclear polarization

    SciTech Connect

    Souers, P. C.; Fearon, E. M.; Mapoles, E. R.; Sater, J. D.; Collins, G. W.; Gaines, J. R.; Sherman, R. H.; Bartlit, J. R.

    1988-01-01

    The expected value of nuclear spin polarization to inertial confinement fusion is recapitulated. A comparison of brute force versus dynamic nuclear polarization, as applied to solid deuterium-tritium, is given, and the need for a long triton polarization memory time (longitudinal nuclear relaxation time) is shown. The time constant for 25 mol%T/sub 2/-50 DT-25 D/sub 2/ is a short 0.3 s at 5/degree/K and waiting lowers it to 0.1 s. Use of 90 to 96 mol% molecular DT raises the time constant to 0.9 s and addition of about 20 mol% nH/sub 2/ increases it to 5 to 7 s. The theory shows that the species shortening the triton memory time is the J = 1 T/sub 2/, which can be reduced in our samples only by self-catalysis. The heating in order to mix in nH/sub 2/ increases the percent of J = 1 T/sub 2/ and mixing may not be perfect. The experiments have increased the triton memory time twenty-fold and shown that removal of the J = 1 T/sub 2/ is the key to improved results.

  18. Psychoanalytic and musical ambiguity: the tritone in gee, officer krupke.

    PubMed

    Jaffee Nagel, Julie

    2010-02-01

    The poignant and timeless Broadway musical West Side Story is viewed from the standpoint of taking musical forms as psychoanalytic data. The musical configuration of notes called the tritone (or diabolus in musica) is taken as a sonic metaphor expressing ambiguity both in musical vocabulary and in mental life. The tritone, which historically and harmonically represents instability, is heard throughout the score and emphasizes the intrapsychic, interpersonal, and social dramas that unfold within and between the two gangs in West Side Story. Particular emphasis is given to the comic but exceedingly sober song Gee, Officer Krupke. Bernstein's sensitivity to the ambiguity and tension inherent in the tritone in West Side Story is conceptualized as an intersection of music theory and theories of mind; this perspective holds implications for clinical practice and transports psychoanalytic concepts from the couch to the Broadway stage and into the community to address the complexities of love, hate, aggression, prejudice, and violence. Ultimately, West Side Story cross-pollinates music and theater, as well as music and psychoanalytic concepts. PMID:20234007

  19. Neptune and Triton: Essential pieces of the Solar System puzzle

    NASA Astrophysics Data System (ADS)

    Masters, A.; Achilleos, N.; Agnor, C. B.; Campagnola, S.; Charnoz, S.; Christophe, B.; Coates, A. J.; Fletcher, L. N.; Jones, G. H.; Lamy, L.; Marzari, F.; Nettelmann, N.; Ruiz, J.; Ambrosi, R.; Andre, N.; Bhardwaj, A.; Fortney, J. J.; Hansen, C. J.; Helled, R.; Moragas-Klostermeyer, G.; Orton, G.; Ray, L.; Reynaud, S.; Sergis, N.; Srama, R.; Volwerk, M.

    2014-12-01

    The planet Neptune and its largest moon Triton hold the keys to major advances across multiple fields of Solar System science. The ice giant Neptune played a unique and important role in the process of Solar System formation, has the most meteorologically active atmosphere in the Solar System (despite its great distance from the Sun), and may be the best Solar System analogue of the dominant class of exoplanets detected to date. Neptune's moon Triton is very likely a captured Kuiper Belt object, holding the answers to questions about the icy dwarf planets that formed in the outer Solar System. Triton is geologically active, has a tenuous nitrogen atmosphere, and is predicted to have a subsurface ocean. However, our exploration of the Neptune system remains limited to a single spacecraft flyby, made by Voyager 2 in 1989. Here, we present the high-level science case for further exploration of this outermost planetary system, based on a white paper submitted to the European Space Agency (ESA) for the definition of the second and third large missions in the ESA Cosmic Vision Programme 2015-2025. We discuss all the major science themes that are relevant for further spacecraft exploration of the Neptune system, and identify key scientific questions in each area. We present an overview of the results of a European-led Neptune orbiter mission analysis. Such a mission has significant scope for international collaboration, and is essential to achieve our aim of understanding how the Solar System formed, and how it works today.

  20. Pitch jnd and the tritone paradox: The linguistic nexus

    NASA Astrophysics Data System (ADS)

    Safari, Kourosh

    2002-11-01

    Previous research has shown a connection between absolute pitch (the ability to name a specific pitch in the absence of any reference) and native competence in a tone language (Deutsch, 1990). In tone languages, tone is one of the features which determines the lexical meaning of a word. This study investigates the relationship between native competence in a tone language and the just noticeable difference of pitch. Furthermore, the tritone paradox studies have shown that subjects hear two tritones (with bell-shaped spectral envelopes) as either ascending or descending depending on their linguistic backgrounds (Deutsch, 1987). It is hypothesized that the native speakers of tone languages have a higher JND for pitch, and hear the two tones of the tritone paradox as ascending, whereas, native speakers of nontone languages hear them as descending. This study will indicate the importance of early musical training for the development of acute tone sensitivity. It will also underline the importance of language and culture in the way it shapes our musical understanding. The significance of this study will be in the areas of music education and pedagogy.

  1. Assembly Methods for Etched Foil Regenerators

    NASA Astrophysics Data System (ADS)

    Mitchell, Matthew P.

    2004-06-01

    Etched foil appears to offer substantial advantages over other regenerator materials, especially for annular regenerators. However, assembly of etched foil regenerators has been difficult because etching regenerator patterns in foil is most satisfactorily accomplished using pieces too small for a complete, spiral-wrapped regenerator. Two techniques have been developed to deal with that problem: For spiral-wrapped regenerators, a new technique for joining pieces of foil using tabs has been successfully employed. The joints are no thicker than the parent material. The tabs substantially fill the holes into which they are locked, virtually eliminating any undesired leak path through the regenerator. The holes constitute breaks in the conductive path through the regenerator. A patent is pending. An alternate method is to insert pieces of foil in a cylindrical housing one at a time. An inflatable bladder presses each newly-inserted piece of foil against the previous layer until both edges slip past each other and contact the previously-installed piece. When the bladder is deflated, the natural springiness of the foil causes the cut edges to seek the wall and meet each other in a butt joint. A patent on the method has been issued; a patent on the resulting regenerator is pending.

  2. Producing carbon stripper foils containing boron

    SciTech Connect

    Stoner, J. O. Jr.

    2012-12-19

    Parameters being actively tested by the accelerator community for the purpose of extending carbon stripper foil lifetimes in fast ion beams include methods of deposition, parting agents, mounting techniques, support (fork) materials, and inclusion of alloying elements, particularly boron. Specialized production apparatus is required for either sequential deposition or co-deposition of boron in carbon foils. A dual-use vacuum evaporator for arc evaporation of carbon and electron-beam evaporation of boron and other materials has been built for such development. Production of both carbon and boron foils has begun and improvements are in progress.

  3. Voyager radio science observations of neptune and triton.

    PubMed

    Tyler, G L; Sweetnam, D N; Anderson, J D; Borutzki, S E; Campbell, J K; Eshleman, V R; Gresh, D L; Gurrola, E M; Hinson, D P; Kawashima, N; Kursinski, E R; Levy, G S; Lindal, G F; Lyons, J R; Marouf, E A; Rosen, P A; Simpson, R A; Wood, G E

    1989-12-15

    The Voyager 2 encounter with the Neptune system included radio science investigations of the masses and densities of Neptune and Triton, the low-order gravitational harmonics of Neptune, the vertical structures of the atmospheres and ionospheres of Neptune and Triton, the composition of the atmosphere of Neptune, and characteristics of ring material. Demanding experimental requirements were met successfully, and study of the large store of collected data has begun. The initial search of the data revealed no detectable effects of ring material with optical depth tau [unknown] 0.01. Preliminary representative results include the following: 1.0243 x 10(26) and 2.141 x 10(22) kilograms for the masses of Neptune and Triton; 1640 and 2054 kilograms per cubic meter for their respective densities; 1355 +/- 7 kilometers, provisionally, for the radius of Triton; and J(2) = 3411 +/- 10(x 10(-6)) and J(4) = -26(+12)(-20)(x10(-6)) for Neptune's gravity field (J>(2) and J(4) are harmonic coefficients of the gravity field). The equatorial and polar radii of Neptune are 24,764 +/- 20 and 24,340 +/- 30 kllometers, respectively, at the 10(5)-pascal (1 bar) pressure level. Neptune's atmosphere was probed to a pressure level of about 5 x 10(5) pascals, and effects of a methane cloud region and probable ammonia absorption below the cloud are evident in the data. Results for the mixing ratios of helium and ammonia are still being investigated; the methane abundance below the clouds is at least 1 percent by volume. Derived temperature-pressure profiles to 1.2 x 10(5) pascals and 78 kelvins (K) show a lapse rate corresponding to "frozen" equilibrium of the para- and ortho-hydrogen states. Neptune's ionosphere exhibits an extended topside at a temperature of 950 +/- 160 K if H(+) is the dominant ion, and narrow ionization layers of the type previously seen at the other three giant planets. Triton has a dense ionosphere with a peak electron concentration of 46 x 10(9) per cubic meter at an

  4. Bonded Invar Clip Removal Using Foil Heaters

    NASA Technical Reports Server (NTRS)

    Pontius, James T.; Tuttle, James G.

    2009-01-01

    A new process uses local heating and temperature monitoring to soften the adhesive under Invar clips enough that they can be removed without damaging the composite underneath or other nearby bonds. Two 1x1 in. (approx.2.5x2.5 cm), 10-W/sq in. (approx.1.6-W/sq cm), 80-ohm resistive foil Kapton foil heaters, with pressure-sensitive acrylic adhesive backing, are wired in parallel to a 50-V, 1-A limited power supply. At 1 A, 40 W are applied to the heater pair. The temperature is monitored in the clip radius and inside the tube, using a dual thermocouple readout. Several layers of aluminum foil are used to speed the heat up, allowing clips to be removed in less than five minutes. The very local heating via the foil heaters allows good access for clip removal and protects all underlying and adjacent materials.

  5. Application of foil bearings to helium turbocompressor

    SciTech Connect

    Chen, H.Ming; Howarth, R.; Bernard, Geren; Theilacker, Jay C.; Soyars, William M.; /Fermilab

    2001-01-01

    Hydrodynamic gas-lubricated foil bearings are ideal for machinery that operates at high speed or in extreme-temperature environments. As motors and generators run at higher speeds with more torque capacity, the need for commonly available, robust, high-speed, low-loss foil bearings is clear. This paper presents an application example of the successful replacement of a tape-type bearing for a bump-type bearing in a helium turbocompressor. Both bearing types are described, as are the steps involved in design and fabrication of the bump bearing, and results of comparison tests between the original and replacement bearings. Methods to analyze bump-type foil bearings with commercially available software are reviewed to further emphasize the inherent simplicity of these bearings. By providing the engineering community with the understanding needed to successfully apply foil bearings, the authors hope that the benefits and true potential of this technology will finally be realized.

  6. Neuroprotection of Grape Seed Extract and Pyridoxine against Triton-Induced Neurotoxicity.

    PubMed

    Abdou, Heba M; Wahby, Mayssaa M

    2016-01-01

    Triton WR-1339 administration causes neurotoxicity. Natural products and herbal extracts can attenuate cerebral injury. In the present study, we investigated the neuroprotective role of grape seed extract and/or vitamin B6 against triton-induced neurotoxicity. Thirty-five adult male albino rats of the Sprague-Dawley strain, weighing 140-145 g, were divided into five groups: control, triton, grape seed extract + triton, grape seed extract + triton + vitamin B6, and vitamin B6 + triton. The hematological and biochemical analyses were carried out. Alteration in iNOS mRNA gene expression was determined using reverse-transcriptase PCR analysis. In addition, qualitative DNA fragmentation was examined using agarose gel electrophoresis. Triton-treatment caused significant disturbances in the hematological parameters, the neurological functions, and the antioxidant profile. Also, triton significantly increased the iNOS mRNA expression and DNA damage. Our results showed that grape seed extract and/or vitamin B6 could attenuate all the examined parameters. These natural substances could exhibit protective effects against triton-induced neurological damage because of their antioxidative and antiapoptotic capacities. PMID:27293516

  7. Triton's surface properties - A preliminary analysis from ground-based, Voyager photopolarimeter subsystem, and laboratory measurements

    NASA Technical Reports Server (NTRS)

    Buratti, B. J.; Lane, A. L.; Gibson, J.; Burrows, H.; Nelson, R. M.; Bliss, D.; Smythe, W.; Garkanian, V.; Wallis, B.

    1991-01-01

    The surface properties of Triton were investigated using data from the ground-based and Voyager photopolarimeter subsystem (PPS) observations of Triton's phase curve. The results indicate that Triton has a high single-scattering albedo (0.96 +/-0.01 at 0.75 micron) and an unusually compacted surface, possibly similar to that of Europa. Results also suggest that Triton's single-particle phase function and the macroscopically rough character of its surface are similar to those of most other icy satellites.

  8. Rotationally resolved midultraviolet studies of Triton and the Pluto/Charon system. I - IUE results

    NASA Technical Reports Server (NTRS)

    Stern, S. A.; Brosch, Noah; Barker, Edwin S.; Gladstone, G. R.

    1991-01-01

    The present uniform analysis of the full set of IUE spectra of Pluto + Charon and Triton attempts to characterize these objects' UV photometric properties variation with rotational phase, giving attention to the 2550-3200 A range. The visible-UV color differentiation increases as Pluto reaches its maximum bolometric brightness; the IUE data suggests that this could be due to a UV surface absorption feature on Pluto or Charon. Typical UV albedos are found on Triton which agree with Voyager photopolarimeter results; Pluto's albedo is much lower than that of Triton, but the amplitude of the Pluto UV lightcurve is greater than that of Triton.

  9. Neuroprotection of Grape Seed Extract and Pyridoxine against Triton-Induced Neurotoxicity

    PubMed Central

    Abdou, Heba M.

    2016-01-01

    Triton WR-1339 administration causes neurotoxicity. Natural products and herbal extracts can attenuate cerebral injury. In the present study, we investigated the neuroprotective role of grape seed extract and/or vitamin B6 against triton-induced neurotoxicity. Thirty-five adult male albino rats of the Sprague-Dawley strain, weighing 140–145 g, were divided into five groups: control, triton, grape seed extract + triton, grape seed extract + triton + vitamin B6, and vitamin B6 + triton. The hematological and biochemical analyses were carried out. Alteration in iNOS mRNA gene expression was determined using reverse-transcriptase PCR analysis. In addition, qualitative DNA fragmentation was examined using agarose gel electrophoresis. Triton-treatment caused significant disturbances in the hematological parameters, the neurological functions, and the antioxidant profile. Also, triton significantly increased the iNOS mRNA expression and DNA damage. Our results showed that grape seed extract and/or vitamin B6 could attenuate all the examined parameters. These natural substances could exhibit protective effects against triton-induced neurological damage because of their antioxidative and antiapoptotic capacities. PMID:27293516

  10. Routine production of a triton beam for an FN accelerator

    SciTech Connect

    McKay, J.W.; Ashbaugh, P.G.; Stark, J.W.

    1985-10-01

    The use of triton beams from tritiated titanium inserts in a sputter ion source has become a significant part of the McMaster Nuclear Physics programme. Tritium beams have been run on the McMaster University FN Tandem since 1978 on the basis of one scheduled running period per year accumulating a total of over 4000 hours of running time. Beams of up to one microamp are routinely put on target. Procedures for safe maintenance and operation of such a source have been developed, and techniques for handling up to 40 TBq (about 1000 Ci) of tritium have been approved by the Atomic Energy Control Board.

  11. Geology of the southern hemisphere of Triton: No polar cap

    NASA Technical Reports Server (NTRS)

    Schenk, P.; Moore, J. M.

    1993-01-01

    The bright southern hemisphere, comprising Uhlanga Regio, is perhaps the most poorly understood geologic province on Triton. The entire bright southern hemisphere has been described as a bright polar 'cap', implying a seasonal origin, or as a permanent geologic terrain distinct from the equatorial terrains. Also, thermal models have predicted seasonal migration of frosts and ices from the presently sun-lit south latitudes to the dark northern latitudes. The distribution of frosts and geologic history of this region must be determined observationally. We reexamine the geology of this terrain with the goal of answering these questions.

  12. Diapirism on Triton - A record of crustal layering and instability

    NASA Technical Reports Server (NTRS)

    Schenk, Paul; Jackson, M. P. A.

    1993-01-01

    Cantaloupe terrain on Neptune's large, icy satellite Triton comprises an organized cellular pattern of noncircular dimples that structurally and geologically most closely resemble salt diapirs exposed on Earth. The mean separation of these cells is 47 km. Modeling of the cells as compositionally driven diapirs suggests that cantaloupe terrain forms by gravity-driven overturn within an ice crust about 20 km thick with a maximum viscosity of 10 exp 22 Pa s. These diapirs probably formed as a result of a density inversion in a layered crust composed partly of ice phases other than water ice.

  13. TRITON: graphic software for rational engineering of enzymes.

    PubMed

    Damboský, J; Prokop, M; Koca, J

    2001-01-01

    Engineering of the catalytic properties of enzymes requires knowledge about amino acid residues interacting with the transition state of the substrate. TRITON is a graphic software package for modelling enzymatic reactions for the analysis of essential interactions between the enzyme and its substrate and for in silico construction of protein mutants. The reactions are modelled using semi-empirical quantum-mechanic methods and the protein mutants are constructed by homology modelling. The users are guided through the calculation and data analysis by wizards. PMID:11252253

  14. Energy balance and plume dynamics in Triton's lower atmosphere

    SciTech Connect

    Yelle, R.V.; Lunine, J.I.; Hunten, D.M. )

    1991-02-01

    The present study of the thermal balance-affecting relationships among Triton lower atmosphere thermal conduction, eddy mixing, condensation, and radiative heating indicates that, while the temperature gradient is negative in the lower atmosphere, it becomes positive at higher altitudes due to the downward conduction of ionospheric heat. This temperature profile is essentially consistent with radio-occultation experiment data; the geyser-like plumes observed by Voyager suggest that the Trioton atmosphere's convective and conductive regions join near 10-km altitude, and that the values inferred for the eddy diffusion and heat-transport coefficients indicate a profile reminiscent of the earth's. 28 refs.

  15. Triton's geyser-like plumes - Discovery and basic characterization

    NASA Technical Reports Server (NTRS)

    Soderblom, L. A.; Becker, T. L.; Kieffer, S. W.; Brown, R. H.; Hansen, C. J.; Johnson, T. V.

    1990-01-01

    One model for the mechanism driving the plumes of the four active geyser-like eruptions observed by Voyager 2 on Triton is a heating up of nitrogen ice in a subsurface greenhouse environment, where nitrogen gas pressurized by solar heating explosively vents to the surface carrying clouds of ice and dark particles into the atmosphere. A temperature increase of less than 4 K above the ambient surface value of 38 + or - 3 K suffices to drive the plumes to 8-km altitude. Each eruption may last a year or more, over the course of which 0.1 cu km of ice is sublimed.

  16. Energy balance and plume dynamics in Triton's lower atmosphere

    NASA Technical Reports Server (NTRS)

    Yelle, Roger V.; Lunine, Jonathan I.; Hunten, Donald M.

    1991-01-01

    The present study of the thermal balance-affecting relationships among Triton lower atmosphere thermal conduction, eddy mixing, condensation, and radiative heating indicates that, while the temperature gradient is negative in the lower atmosphere, it becomes positive at higher altitudes due to the downward conduction of ionospheric heat. This temperature profile is essentially consistent with radio-occultation experiment data; the geyser-like plumes observed by Voyager suggest that the Trioton atmosphere's convective and conductive regions join near 10-km altitude, and that the values inferred for the eddy diffusion and heat-transport coefficients indicate a profile reminiscent of the earth's.

  17. The interaction of phosphatidylcholine bilayers with Triton X-100.

    PubMed

    Goñi, F M; Urbaneja, M A; Arrondo, J L; Alonso, A; Durrani, A A; Chapman, D

    1986-11-01

    The interaction of multilamellar phosphatidylcholine vesicles with the non-ionic detergent Triton X-100 has been studied under equilibrium conditions, specially in the sub-lytic range of surfactant concentrations. Equilibrium was achieved in less than 24 h. Estimations of detergent binding to bilayers, using [3H]Triton X-100, indicate that the amphiphile is incorporated even at very low concentrations (below its critical micellar concentration); a dramatic increase in the amount of bound Triton X-100 occurs at detergent concentrations just below those producing membrane solubilization. Solubilization occurs at phospholipid/detergent molar ratios near 0.65 irrespective of lipid concentration. The perturbation produced by the surfactant in the phospholipid bilayer has been studied by differential scanning calorimetry, NMR and Fourier-transform infrared spectroscopy. At low detergent concentration (lipid/detergent molar ratios above 3), a reduction in 2H-NMR quadrupolar splitting occurs, suggesting a decrease in the static order of the acyl chains; the same effect is detected by Fourier-transform infrared spectroscopy in the form of blue shifts of the methylene stretching vibration bands. Simultaneously, the enthalpy variation of the main phospholipid phase transition is decreased by about a third with respect to its value in the pure lipid/water system. For phospholipid/detergent molar ratios between 3 and 1, the decrease in lipid static order does not proceed any further; rather an increase in fluidity is observed, characterized by a marked decrease in the midpoint transition temperature of the gel-to-fluid phospholipid transition. At the same time an isotropic component is apparent in both 31P-NMR and 2H-NMR spectra, and a new low-temperature endotherm is detected in differential scanning calorimetric traces. When phospholipid and Triton X-100 are present at equimolar ratios some bilayer structure persists, as judged from calorimetric observations, but NMR reveals

  18. Diapirism on Triton - A record of crustal layering and instability

    NASA Astrophysics Data System (ADS)

    Schenk, Paul; Jackson, M. P. A.

    1993-04-01

    Cantaloupe terrain on Neptune's large, icy satellite Triton comprises an organized cellular pattern of noncircular dimples that structurally and geologically most closely resemble salt diapirs exposed on Earth. The mean separation of these cells is 47 km. Modeling of the cells as compositionally driven diapirs suggests that cantaloupe terrain forms by gravity-driven overturn within an ice crust about 20 km thick with a maximum viscosity of 10 exp 22 Pa s. These diapirs probably formed as a result of a density inversion in a layered crust composed partly of ice phases other than water ice.

  19. Cryostat with Foil and MLI

    SciTech Connect

    Hwang, Peter K.F.; Gung, Chen-yu

    2005-10-06

    Induction cores are used to accelerate heavy ion beam array, which are built around the outer diameter of the cryostat housing the superconducting quadruple array. Compact cryostat is highly desirable to reduce the cost of the induction cores. Recent experiences in fabrication of a cryostat for single beam transport revealed that it is possible to reduce the spacing in the cryostat vacuum jacket by using low-emissivity thermal insulation material instead of conventional MLI. However, it is labor-intensive to install the new type of insulation as compared with using MLI. It is promising to build a cost-effective compact cryostat for quadruple magnet array for heavy ion beam array transport by using low-emissivity material combined with conventional MLI as radiation insulation. A matrix of insulation designs and tests will be performed as the feasibility study and for the selection of the optimal thermal insulation as the Phase I work. The selected mixed insulation will be used to build prototype compact cryostats in the Phase II project, which are aiming for housing quadruple doublet array. In this STTR phase I study, a small cryostat has been designed and built to perform calorimetric characterization of the heat load in a liquid helium vessel insulated with a vacuum layer with a nominal clearance of 3.5 mm. The vacuum clearance resembled that used in the warm-bore beam tube region in a prototype cryostat previously built for the heavy ion beam transport experiment. The vacuum clearance was geometrically restricted with a heater shell with the temperature controlled at near 300 K. Various combinations of radiation and thermal shields were installed in the tight vacuum clearance for heat load measurements. The measured heat loads are reported and compared with previous test result using a compact vacuum layer. Further developments of the thermal insulations used in the present study are discussed. The compact cryostat with foil and MLI insulation may be used in the

  20. Scatterers in Triton's atmosphere - Implications for the seasonal volatile cycle

    NASA Technical Reports Server (NTRS)

    Pollack, James B.; Schwartz, Joel M.; Rages, Kathy

    1990-01-01

    Nitrogen and methane ices on the surface of Triton, Neptune's largest satellite, are exchanged between the summer and winter hemispheres on a seasonal time scale. Images of the satellite's sky obtained by the Voyager 2 spacecraft show the presence of several types of scattering materials that provide insights into this seasonal cycle of volatiles. Discrete clouds, probably composed of N2 ice particles, arise in regions of active sublimation. They are found chiefly poloward of 30 deg S in the southern, summer hemisphere. Haze particles, probably made of hydrocarbon ices, are present above most, but not all places. Recent snowfall may have occurred at low southern latitudes in places where they are absent. The latent heat released in the formation of the discrete clouds may have a major impact on the thermal balance of the lower atmosphere. Triton may have been less red at the time of the Voyager flyby than 12 years earlier due to recent N2 snowfall at a wide range of latitudes.

  1. The nature of the hydrogen tori of Titan and Triton

    NASA Technical Reports Server (NTRS)

    Smyth, William H.; Marconi, M. L.

    1993-01-01

    The nature of the hydrogen tori of Titan and Triton is examined. Critical time scales of the two tori are discussed. For the Titan torus, where atom-atom collisions are not important, the time scale for solar radiation pressure to act on the system is shown to be comparable to the hydrogen lifetime due to ionization and charge exchange losses by solar, magnetospheric, and solar wind processes. The solar radiation pressure then provides a mechanism which destroys the initial azimuthal symmetry of the hydrogen atom orbits about the planet and causes atom orbits to move inward and to collide with the planet on its dusk side. For Triton, the atom-atom collision time scale dominates all other time scales in the system. The evolution of the torus is then an inherently nonlinear problem that depends upon the collisional redistribution of atom-orbit velocities in the presence of a planetary gravitational force field. This nonlinear process introduces an expansion mechanism into the torus problem which dramatically alters its structure.

  2. The role of nonuniform internal heating in Triton's energy budget

    NASA Technical Reports Server (NTRS)

    Kirk, R. L.; Brown, R. H.

    1991-01-01

    Triton's large heliocentric distance and high albedo, combined with its unusually large silicate mass fraction, make internal heating more important in its energy budget than in that of any other icy satellite. Brown et al. have recently estimated that the average radiogenic heat flux (which is probably between 3.3 and 6.6 mW/sq m depending on core size and composition) may equal 5 to 20 pct. of the average absorbed insolation. On a global scale, this additional energy input appreciably increases the thermal emissivity required to be consistent with the observed surface temperature. Brown et al. also speculated that spatial variations of the internal flux may change the local sublimation deposition balance enough to lead to observable modifications of the distribution of volatiles on Triton's surface. An attempt is made to estimate the magnitude of internal heat flux variations due to the insulating effect of the polar caps, to mantle convection, and to cryovolcanism; the importance is evaluated of these variations in modifying the volatile distribution.

  3. USE OF ENZYME-LINKED IMMUNOSORBENT ASSAYS (ELISA) FOR THE DETERMINATION OF TRITON X NONIONIC DETERGENTS

    EPA Science Inventory

    An enzyme-linked immunosorbent assay (ELISA) for 4-t-octylphenyl ethoxylates such as Triton X-100 was developed. Both the 4-t-octylphenyl and the ethoxylate moiety were required for antibody recognition since members of the Triton N series showed low cross-reactivity, and polyeth...

  4. Effects of Triton X-100 nanoaggregates on dimerization and antioxidant activity of morin.

    PubMed

    Liu, Weiya; Guo, Rong

    2008-01-01

    Dimerization and antioxidant activity of morin in the Triton X-100 micelles were studied by electronic absorption, ATR-FTIR spectra, cyclic voltammetric, DSC, freeze-fracture TEM, molecular modeling and ab initio quantum calculations. Morin can be solubilized in the Triton X-100 micelles and show selective dimerization in Triton X-100 micelles with different structures. In Triton X-100 spherical micelles, morin always exists in the form of dimer, and in Triton X-100 rodlike micelles, it is always in the form of monomer. The solubilization of morin dimer in Triton X-100 spherical micelles changes the micelle morphology from spherical to cubelike, and the size of the single micelle is also increased, while morin monomer links the Triton X-100 rodlike micelles and forms a kind of network micelle structure with the size of the "rod" unchanged. Solubilized and concentrated in Triton X-100 micelles, morin can protect human serum albumin from the damage induced by hydroxyl radicals effectively and even can form a kind of protein complex with human serum albumin showing more thermal stability. PMID:18510337

  5. Status of Genesis Mo-Pt Foils

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Allton, J. H.; Burnett, D. S.; Butterworth, A. L.; Caffee, M. W.; Clark, B.; Jurewicz, A. J. G.; Komura, K.; Westphal, A. J.; Welten, K. C.

    2005-01-01

    A total of 8,000 sq cm of Mo-coated Pt foils were exposed to solar wind for 884 days by the Genesis mission. Solar wind ions were captured in the surface of the Mo. Our objective is the measurement of long-lived radionuclides, such as Be-10, Al-26, Cl-36, and Mn-53, and short-lived radionuclides, such as Na-22 and Mn-54, in the captured sample of solar wind. The expected flux of these nuclides in the solar wind is 100 atom/sq cm yr or less. The hard landing of the SRC (Sample Return Capsule) at UTTR (Utah Test and Training Range) has resulted in contaminated and crumpled foils. Here we present a status report and revised plan for processing the foils.

  6. Two High-Temperature Foil Journal Bearings

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2006-01-01

    An enlarged, high-temperature-compliant foil bearing has been built and tested to demonstrate the feasibility of such bearings for use in aircraft gas turbine engines. Foil bearings are attractive for use in some machines in which (1) speeds of rotation, temperatures, or both exceed maximum allowable values for rolling-element bearings; (2) conventional lubricants decompose at high operating temperatures; and/or (3) it is necessary or desirable not to rely on conventional lubrication systems. In a foil bearing, the lubricant is the working fluid (e.g., air or a mixture of combustion gases) in the space between the journal and the shaft in the machine in which the bearing is installed.

  7. Stability of Triton's Albedo from 1985 Through 1997: Implications for the Atmosphere

    NASA Technical Reports Server (NTRS)

    Hammel, Heidi B.

    2000-01-01

    Recent occultation results indicate that an increase in temperature may have occurred in the atmosphere of Triton during the past 8 years (Elliot et al. 1998; Olkin et al. 1997). The atmosphere is thought to be in vapor pressure equilibrium with the surface frosts, hence changes in frost coverage can have significant implications for atmospheric stability. We have a long- term set of multiwavelength data on Triton spanning more than a decade (the data were obtained for Neptune observations, but Triton is visible in most of the images). Over that time, the data were obtained with nearly identical filters. Thus far, only one year's worth of one wavelength has been analyzed for Triton (Lark et al. 1989). We proposed to complete a comprehensive and self-consistent analysis of the complete Triton data set. One year was funded of a requested three-year program.

  8. Diffusion of hydrogen in zirconium foil

    SciTech Connect

    Schur, D.V.; Pishuk, V.K.; Adejev, V.M.; Zaginaichenko, S.Y.

    1998-12-31

    The authors of present research have used in experiments the atomic hydrogen and metallic foil 25--30 {micro}m thick. It has been supposed that these technical operations will permit excluding the influence of surface and diffusional processes on the rate of Me-H interaction. The series of experiments have been carried out and they confirm this assumption. It has been shown that hydrogenation reaction of zirconium foil in atomic hydrogen conforms to the topochemical model of volume segregation of interaction product, and the rate of its flow is independent of the surface processes and hydrogen diffusion in volume.

  9. Method of high-density foil fabrication

    DOEpatents

    Blue, Craig A.; Sikka, Vinod K.; Ohriner, Evan K.

    2003-12-16

    A method for preparing flat foils having a high density includes the steps of mixing a powdered material with a binder to form a green sheet. The green sheet is exposed to a high intensity radiative source adapted to emit radiation of wavelengths corresponding to an absorption spectrum of the powdered material. The surface of the green sheet is heated while a lower sub-surface temperature is maintained. An apparatus for preparing a foil from a green sheet using a radiation source is also disclosed.

  10. Compressor ported shroud for foil bearing cooling

    DOEpatents

    Elpern, David G.; McCabe, Niall; Gee, Mark

    2011-08-02

    A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

  11. Steel Foil Improves Performance Of Blasting Caps

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Perry, Ronnie; Schimmel, Morry L.

    1990-01-01

    Blasting caps, which commonly include deep-drawn aluminum cups, give significantly higher initiation performance by application of steel foils on output faces. Steel closures 0.005 in. (0.13 mm) thick more effective than aluminum. Caps with directly bonded steel foil produce fragment velocities of 9,300 ft/s (2.8 km/s) with large craters and unpredictable patterns to such degree that no attempts made to initiate explosions. Useful in military and aerospace applications and in specialized industries as mining and exploration for oil.

  12. Thrust augmentation in tandem flapping foils by foil-wake interaction

    NASA Astrophysics Data System (ADS)

    Anderson, Erik; Lauder, George

    2006-11-01

    Propulsion by pitching and heaving airfoils and hydrofoils has been a focus of much research in the field of biologically inspired propulsion. Organisms that use this sort of propulsion are self-propelled, so it is difficult to use standard experimental metrics such as thrust and drag to characterize performance. We have constructed a flapping foil robot mounted in a flume on air-bearings that allows for the determination of self-propelled speed as a metric of performance. We have used a pair of these robots to examine the impact of an upstream flapping foil on a downstream flapping foil as might apply to tandem fins of a swimming organism or in-line swimming of schooling organisms. Self-propelled speed and a force transducer confirmed significant thrust augmentation for particular foil-to-foil spacings, phase differences, and flapping frequencies. Flow visualization shows the mechanism to be related to the effective angle of attack of the downstream foil due to the structure of the wake of the upstream foil. This confirms recent computational work and the hypotheses by early investigators of fish fluid dynamics.

  13. A search for ethane on Pluto and Triton

    NASA Astrophysics Data System (ADS)

    DeMeo, Francesca E.; Dumas, Christophe; de Bergh, Catherine; Protopapa, Silvia; Cruikshank, Dale P.; Geballe, Thomas R.; Alvarez-Candal, Alvaro; Merlin, Frédéric; Barucci, Maria A.

    2010-07-01

    We present here a search for solid ethane, C 2H 6, on the surfaces of Pluto and Triton, based on near-infrared spectral observations in the H and K bands (1.4-2.45 μm) using the Very Large Telescope (VLT) and the United Kingdom Infrared Telescope (UKIRT). We model each surface using a radiative transfer model based on Hapke theory (Hapke, B. [1993]. Theory of Reflectance and Emittance Spectroscopy. Cambridge University Press, Cambridge, UK) with three basic models: without ethane, with pure ethane, and with ethane diluted in nitrogen. On Pluto we detect weak features near 2.27, 2.405, 2.457, and 2.461 μm that match the strongest features of pure ethane. An additional feature seen at 2.317 μm is shifted to longer wavelengths than ethane by at least 0.002 μm. The strength of the features seen in the models suggests that pure ethane is limited to no more than a few percent of the surface of Pluto. On Triton, features in the H band could potentially be explained by ethane diluted in N, however, the lack of corresponding features in the K band makes this unlikely (also noted by Quirico et al. (Quirico, E., Doute, S., Schmitt, B., de Bergh, C., Cruikshank, D.P., Owen, T.C., Geballe, T.R., Roush, T.L. [1999]. Icarus 139, 159-178)). While Cruikshank et al. (Cruikshank, D.P., Mason, R.E., Dalle Ore, C.M., Bernstein, M.P., Quirico, E., Mastrapa, R.M., Emery, J.P., Owen, T.C. [2006]. Bull. Am. Astron. Soc. 38, 518) find that the 2.406-μm feature on Triton could not be completely due to 13CO, our models show that it could not be accounted for entirely by ethane either. The multiple origin of this feature complicates constraints on the contribution of ethane for both bodies.

  14. A Neptune/Triton Vision Mission Using Nuclear Electric Propulsion

    NASA Astrophysics Data System (ADS)

    Steffes, P.; Bienstock, B.; Atkinson, D. H.; Baines, K.; Mahaffey, P.; Atreya, S.; Stern, A.; Wright, M.

    2004-12-01

    The giant planets of the outer solar system divide into two distinct classes: the `gas giants' Jupiter and Saturn, primarily comprising hydrogen and helium; and the `ice giants' Uranus and Neptune that are believed to contain significant amounts of the heavier elements including oxygen, nitrogen, carbon, and sulfur. Detailed comparisons of the internal structures and compositions of the gas giants with those of the ice giants will yield valuable insights into the processes that formed the solar system and, perhaps, extrasolar systems. By 2012, Pioneer, Voyager, Galileo, Cassini, and possibly a New Frontiers Jupiter mission will have yielded significant information on the chemical and physical properties of Jupiter and Saturn. A Neptune mission would deliver the corresponding key data for an ice giant planet. A Neptune Orbiter with Probes mission utilizing nuclear electric propulsion (NEP) to study Triton, Nereid, the other icy satellites of Neptune, Neptune's system of rings, and the deep Neptune atmosphere to pressures ranging from several hundred bars to possibly several kilobars is being examined. Power and propulsion would be provided using nuclear electric technologies. Such an ambitious mission requires a number of technical issues be investigated and resolved, including: (1) developing a realizable mission design that allows proper targeting and timing of the entry probe(s) while offering adequate opportunities for detailed measurements of Triton, the other icy satellites and ring science, (2) giant-planet atmospheric probe thermal protection system (TPS) design, (3) descent probe design including seals, windows, penetrations and inlets, and pressure vessel, (4) probe telecommunications through the dense and absorbing Neptunian atmosphere, and (5) within NEP mass and power constraints, defining an appropriate suite of science instruments to explore the depths of the Neptune atmosphere, magnetic field, Triton, and the icy satellites. Another driving factor in

  15. Spallation Neutron Source SNS Diamond Stripper Foil Development

    SciTech Connect

    Shaw, Robert W; Plum, Michael A; Wilson, Leslie L; Feigerle, Charles S.; Borden, Michael J.; Irie, Y.; Sugai, I; Takagi, A

    2007-01-01

    Diamond stripping foils are under development for the SNS. Freestanding, flat 300 to 500 {micro}g/cm{sup 2} foils as large as 17 x 25 mm{sup 2} have been prepared. These nano-textured polycrystalline foils are grown by microwave plasma-assisted chemical vapor deposition in a corrugated format to maintain their flatness. They are mechanically supported on a single edge by a residual portion of their silicon growth substrate; fine foil supporting wires are not required for diamond foils. Six foils were mounted on the SNS foil changer in early 2006 and have performed well in commissioning experiments at reduced operating power. A diamond foil was used during a recent experiment where 15 {micro}C of protons, approximately 64% of the design value, were stored in the ring. A few diamond foils have been tested at LANSCE/PSR, where one foil was in service for a period of five months (820 C of integrated injected charge) before it was replaced. Diamond foils have also been tested in Japan at KEK (640 keV H{sup -}) where their lifetimes slightly surpassed those of evaporated carbon foils, but fell short of those for Sugai's new hybrid boron carbon (HBC) foils.

  16. Tight, Flat, Smooth, Ultrathin Metal Foils for Locating Synchrotron Beams

    NASA Astrophysics Data System (ADS)

    Jolivet, Connie S.; Stoner, John O.

    2007-01-01

    It is often desired to locate a synchrotron x-ray beam precisely in space with minimal disturbance of its spatial profile and spectral content. This can be done by passing the beam through an ultrathin, flat, smooth metal foil having well-defined composition, preferably a single chemical element such as chromium, titanium or aluminum. Localized fluorescence of the foil at characteristic x-ray lines where the x-ray beam passes through the foil serves to locate the beam in two dimensions. Use of two such foils along the beam direction locates the x-ray beam spatially and identifies precisely its direction. The accuracy of determining these parameters depends in part upon high uniformity in the thickness of the foil(s), good planarity, and smoothness of the foil(s). In practice, several manufacturing steps to produce a foil must be carried out with precision. The foil must be produced on a smooth removable substrate in such a way that its thickness (or areal density) is as uniform as possible. The foil must be fastened to a support ring that maintains the foil's surface quality, and it must be then stretched onto a frame that produces the desired mirror flatness. These steps are illustrated and some of the parameters specifying the quality of the resulting foils are identified.

  17. Origin of the Earths's Moon and Neptune's Triton

    NASA Astrophysics Data System (ADS)

    Johnson, Fred

    2015-08-01

    In view of the recently reported chemical similarities between lunar and earth specimen, interest in the lunar origin has been reawakened. A new approach is presented here. A necessary condition for a lunar spin-off requires that the primitive earth has expanded since its inception. Then, utilizing the non-controversial conservation of total angular momentum of the earth-moon system, one can readily derive the initial physical conditions for the moon's escape (spin-off) from the upper surface of a rapidly spinning, diminutive earth. Detailed calculations will be presented for both the Moon-Earth and Triton-Neptune's early evolutionary developments. The results have implications to theories relating the origin of the solar system.

  18. The effect of surface roughness on Triton's volatile distribution

    NASA Technical Reports Server (NTRS)

    Yelle, Roger V.

    1992-01-01

    Calculations of radiative equilibrium temperatures on Triton's rough surface suggest that significant condensation of N2 may be occurring in the northern equatorial regions, despite their relatively dark appearance. The bright frost is not apparent in the Voyager images because it tends to be concentrated in relatively unilluminated facets of the surface. This patchwork of bright frost-covered regions and darker bare ground may be distributed on scales smaller than that of the Voyager resolution; as a result the northern equatorial regions may appear relatively dark. This hypothesis also accounts for the observed wind direction in the Southern Hemisphere because it implies that the equatorial regions are warmer than the south polar regions.

  19. Properties of haze in the atmosphere of Triton

    NASA Technical Reports Server (NTRS)

    Krasnopolsky, V. A.; Sandel, B. R.; Herbert, F.

    1992-01-01

    Voyager UV spectrometer measurements of CH4 and haze of the Triton atmosphere combined with the haze brightness profile determined by the narrow angle camera are used to infer a haze optical thickness of 0.024 at 1500 A and 0.0078 in the spectral range of the narrow angle camera centered at 4700A, rho/gamma = 0.36 +/- 0.1 g/cu cm (gamma is the quantum yield of condensate), and values of r(c) varying from 0.1 +/- 0.02 micron at 30 km to 0.15 +/- 0.03 micron near the surface. Other auxiliary properties of the haze are also determined. The value found for rho/gamma corresponds to a packing coefficient of 0.6 gamma if C2H4 is the main condensible species.

  20. Surface and airborne evidence for plumes and winds on triton

    USGS Publications Warehouse

    Hansen, C.J.; McEwen, A.S.; Ingersoll, A.P.; Terrile, R.J.

    1990-01-01

    Aeolian features on Triton that were imaged during the Voyager Mission have been grouped. The term "aeolian feature" is broadly defined as features produced by or blown by the wind, including surface and airborne materials. Observations of the latitudinal distributions of the features probably associated with current activity (known plumes, crescent streaks, fixed terminator clouds, and limb haze with overshoot) all occur from latitude -37?? to latitude -62??. Likely indicators of previous activity (dark surface streaks) occur from latitude -5?? to -70??, but are most abundant from -15?? to -45??, generally north of currently active features. Those indicators which give information on wind direction and speed have been measured. Wind direction is a function of altitude. The predominant direction of the surface wind streaks is found to be between 40?? and 80?? measured clockwise from north. The average orientation of streaks in the northeast quadrant is 59??. Winds at 1- to 3-kilometer altitude are eastward, while those at >8 kilometers blow west.

  1. Measurements of energetic confined alphas and tritons on TFTR

    SciTech Connect

    Medley, S.S.; Duong, H.H.; McChesney, J.M.

    1995-08-01

    In a collaboration involving General Atomics, the A. F. Ioffe Physical-Technical Institute, and the Princeton Plasma Physics Laboratory, the energy distribution of the fast-confined alpha particles in DT experiments on TFIR is being measured by active neutral particle analysis using the ablation cloud surrounding an injected impurity pellet as the neutralizer. Recent papers reported the first measurements of the energy distribution fast confined alpha particles and examined the influence of magnetic field ripple and sawtooth oscillations on the behavior of the alpha energy spectra and radial density distributions. This paper focuses on alpha and triton measurements in the core of quiescent TFTR discharges where the expected classical slowing down and pitch angle scattering effects are not complicated by stochastic ripple diffusion and sawtooth activity.

  2. Proteome analysis of the triton-insoluble erythrocyte membrane skeleton.

    PubMed

    Basu, Avik; Harper, Sandra; Pesciotta, Esther N; Speicher, Kaye D; Chakrabarti, Abhijit; Speicher, David W

    2015-10-14

    Erythrocyte shape and membrane integrity is imparted by the membrane skeleton, which can be isolated as a Triton X-100 insoluble structure that retains the biconcave shape of intact erythrocytes, indicating isolation of essentially intact membrane skeletons. These erythrocyte "Triton Skeletons" have been studied morphologically and biochemically, but unbiased proteome analysis of this substructure of the membrane has not been reported. In this study, different extraction buffers and in-depth proteome analyses were used to more fully define the protein composition of this functionally critical macromolecular complex. As expected, the major, well-characterized membrane skeleton proteins and their associated membrane anchors were recovered in good yield. But surprisingly, a substantial number of additional proteins that are not considered in erythrocyte membrane skeleton models were recovered in high yields, including myosin-9, lipid raft proteins (stomatin, flotillin1 and 2), multiple chaperone proteins (HSPs, protein disulfide isomerase and calnexin), and several other proteins. These results show that the membrane skeleton is substantially more complex than previous biochemical studies indicated, and it apparently has localized regions with unique protein compositions and functions. This comprehensive catalog of the membrane skeleton should lead to new insights into erythrocyte membrane biology and pathogenic mutations that perturb membrane stability. Biological significance Current models of erythrocyte membranes describe fairly simple homogenous structures that are incomplete. Proteome analysis of the erythrocyte membrane skeleton shows that it is quite complex and includes a substantial number of proteins whose roles and locations in the membrane are not well defined. Further elucidation of interactions involving these proteins and definition of microdomains in the membrane that contain these proteins should yield novel insights into how the membrane skeleton

  3. Thermal Sensitive Foils in Physics Experiments

    ERIC Educational Resources Information Center

    Bochnícek, Zdenek; Konecný, Pavel

    2014-01-01

    The paper describes a set of physics demonstration experiments where thermal sensitive foils are used for the detection of the two dimensional distribution of temperature. The method is used for the demonstration of thermal conductivity, temperature change in adiabatic processes, distribution of electromagnetic radiation in a microwave oven and…

  4. Hydrogen and Palladium Foil: Two Classroom Demonstrations

    ERIC Educational Resources Information Center

    Klotz, Elsbeth; Mattson, Bruce

    2009-01-01

    In these two classroom demonstrations, students observe the reaction between H[subscript 2] gas and Pd foil. In the first demonstration, hydrogen and palladium combine within one minute at 1 atm and room temperature to yield the non-stoichiometric, interstitial hydride with formula close to the maximum known value, PdH[subscript 0.7]. In the…

  5. Foil Panel Mirrors for Nonimaging Applications

    NASA Technical Reports Server (NTRS)

    Kuyper, D. J.; Castillo, A. A.

    1984-01-01

    Large durable, lightweight mirrors made by bonding thick aluminum foil to honeycomb panels or other rigid, flat backings. Mirrors suitable for use as infrared shields, telescope doors, solar-furnance doors, advertising displays, or other reflectors that require low thermal emissivity and high specularity but do not require precise surface figure necessary for imaging.

  6. Indium Foil Serves As Thermally Conductive Gasket

    NASA Technical Reports Server (NTRS)

    Eastman, G. Yale; Dussinger, Peter M.

    1993-01-01

    Indium foil found useful as gasket to increase thermal conductance between bodies clamped together. Deforms to fill imperfections on mating surfaces. Used where maximum temperature in joint less than melting temperature of indium. Because of low melting temperature of indium, most useful in cryogenic applications.

  7. Strong field electrodynamics of a thin foil

    SciTech Connect

    Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Bulanov, Stepan S.; Rykovanov, Sergey G.; Pegoraro, Francesco

    2013-12-15

    Exact solutions describing the nonlinear electrodynamics of a thin double layer foil are presented. These solutions correspond to a broad range of problems of interest for the interaction of high intensity laser pulses with overdense plasmas, such as frequency upshifting, high order harmonic generation, and high energy ion acceleration.

  8. The Fluid Foil: The Seventh Simple Machine

    ERIC Educational Resources Information Center

    Mitts, Charles R.

    2012-01-01

    A simple machine does one of two things: create a mechanical advantage (lever) or change the direction of an applied force (pulley). Fluid foils are unique among simple machines because they not only change the direction of an applied force (wheel and axle); they convert fluid energy into mechanical energy (wind and Kaplan turbines) or vice versa,…

  9. Analytical theory of motion and new ephemeris of Triton from observations

    NASA Astrophysics Data System (ADS)

    Emelyanov, N. V.; Samorodov, M. Yu.

    2015-12-01

    Modelling the motion of Triton, the main satellite of Neptune, is specific. Earlier researchers built Triton's ephemeris by numerical integration of the equations of its motion. However, these ephemeris can be accessed only by using online ephemeris server or by borrowing a special calculating program and huge data file from authors of the ephemeris. In addition, the interval of the earlier ephemeris is limited. In this paper, simple and easily programmable formulae are presented for computing Triton's ephemeris for any instant of time. The formulae are based on a new analytical theory of Triton's motion all necessary perturbing factors being taken into consideration. The parameters of the theory are fit to all published observations made from 1847 to 2012 (10 254 observations in total). After the parameters were fit to observations, the root-mean-square residuals were 0.228 arcsec, the weighted average residual being 0.036 arcsec. The new ephemeris of Triton slightly differs from those produced by other authors because of differences in the sets of used observations. The new ephemeris of Triton are put on our online ephemeris server. It is shown that the available observations do not allow to determine reliably the quadratic term in the orbital longitude of Triton. Such a term would be an additional indicator of the accuracy of the theory and observations.

  10. Triton X-100 pretreatment of LR-white thin sections improves immunofluorescence specificity and intensity.

    PubMed

    Ghrebi, Salem S; Owen, Gethin Rh; Brunette, Donald M

    2007-07-01

    The staining of intracellular antigenic sites in postembedded samples is a challenging problem. Deterioration of antigenicity and limited antibody accessibility to the antigen are commonly encountered on account of processing steps. In this study preservation of the antigen was achieved by fixing the tissues with mild fixatives, performing partial dehydration, and embedding in a low crosslinked hydrophilic acrylic resin, LR-White. Permeabilization of cell membranes with Triton X-100 is well documented but can affect some antigen conformations. We tested the effect of Triton X-100 on the ED1 antigen present in the lysosomal membrane of the macrophage in cell culture. The ED1 antigen in the lysosome was resistant to extraction by Triton X-100. Interestingly pretreating the LR-White sections of macrophage pellets with Triton X-100 improved the staining intensity of ED1. The most intense and clear specific fluorescent staining was observed when sections were pretreated with 0.2% Triton X-100 for 2 min. Longer exposure of sections to 0.2% Triton or 2 min exposure to 2% Triton lead to reduced ED1 labeling. SEM observations indicated that the detergent extracted a component from the cells and not the resin and was determined to be lipid. This novel technique could be applied in many research areas where postembedding fluorescent immunolabeling with higher labeling intensity is desired. PMID:17380496

  11. Some remarks on the capture of Triton and the origin of Pluto

    NASA Astrophysics Data System (ADS)

    Farinella, P.; Milani, A.; Nobili, A. M.; Valsecchi, G. B.

    1980-12-01

    Harrington and Van Flandern (1979, Icarus39, 131-136) suggests that the irregular features of the Neptunian satellite system and Pluto's escape were caused by an encounter with a massive external body. They rule out the alternative mechanism based on the capture of Triton (which seems more plausible because it does not appeal to any unobserved object) on the basis of an incorrect deduction from McCord's (1966, Astron. J.71, 585-590) analysis on the tidal decay of Triton's orbit. As a matter of fact, many recent results show that satellite captures are possible, and in the case of Triton several arguments support this interpretation.

  12. Surfactant-enhanced remediation of a trichloroethene-contaminated aquifer. 1. Transport of triton X-100

    USGS Publications Warehouse

    Smith, J.A.; Sahoo, D.; Mclellan, H.M.; Imbrigiotta, T.E.

    1997-01-01

    Transport of a nonionic surfactant (Triton X-100) at aqueous concentrations less than 400 mg/L through a trichloroethene-contaminated sand-and-gravel aquifer at Picatinny Arsenal, NJ, has been studied through a series of laboratory and field experiments. In the laboratory, batch and column experiments were conducted to quantify the rate and amount of Triton X-100 sorption to the aquifer sediments. In the field, a 400 mg/L aqueous Triton X-100 solution was injected into the aquifer at a rate of 26.5 L/min for a 35-d period. The transport of Triton X-100 was monitored by sampling and analysis of groundwater at six locations surrounding the injection well. Equilibrium batch sorption experiments showed that Triton X-100 sorbs strongly and nonlinearly to the field soil with the sharpest inflection point of the isotherm occurring at an equilibrium aqueous Triton X-100 concentration close to critical micelle concentration. Batch, soil column, and field experimental data were analyzed with zero-, one-, and two- dimensional (respectively) transient solute transport models with either equilibrium or rate-limited sorption. These analyses reveal that Triton X- 100 sorption to the aquifer solids is slow relative to advective and dispersive transport and that an equilibrium sorption model cannot simulate accurately the observed soil column and field data. Comparison of kinetic sorption parameters from batch, column, and field transport data indicate that both physical heterogeneities and Triton X-100 mass transfer between water and soil contribute to the kinetic transport effects.Transport of a nonionic surfactant (Triton X-100) at aqueous concentrations less than 400 mg/L through a trichloroethene-contaminated sand-and-gravel aquifer was studied. Equilibrium batch sorption experiments showed that Triton X-100 sorbs strongly and nonlinearly to the field soil with the sharpest inflection point of the isotherm occurring at an equilibrium aqueous Triton X-100 concentration close to

  13. The influence of thermal inertia on temperatures and frost stability on Triton

    NASA Technical Reports Server (NTRS)

    Spencer, John R.; Moore, Jeffrey M.

    1992-01-01

    It is presently argued, in view of (1) a thermal inertia model for the surface of Triton which (like previous ones) predicts a monotonic recession of permanent N2 deposits toward the poles and very little seasonal N2 frost in the southern hemisphere, and (2) new spectroscopic evidence for nonvolatile CO2 on Triton's bright southern hemisphere, that much of that bright southern material is not N2. Such bright southern hemisphere volatiles may allow the formation of seasonal frosts, thereby helping to explain the observed spectroscopic changes of Triton during the last decade.

  14. Optical and electrical performance of commercially manufactured large GEM foils

    NASA Astrophysics Data System (ADS)

    Posik, M.; Surrow, B.

    2015-12-01

    With interest in large area GEM foils increasing and CERN being the only main distributor, keeping up with the demand for GEM foils will be difficult. Thus the commercialization of GEMs is being established by Tech-Etch of Plymouth, MA, USA using single-mask techniques. We report here on the first of a two step quality verification of the commercially produced 10×10 cm2 and 40×40 cm2 GEM foils, which includes characterizing their electrical and geometrical properties. We have found that the Tech-Etch foils display excellent electrical properties, as well as uniform and consistent hole diameters comparable to established foils produced by CERN.

  15. Nuclear target foil fabrication for the Romano Event

    SciTech Connect

    Weed, J.W.; Romo, J.G. Jr.; Griggs, G.E.

    1984-06-19

    The Vacuum Processes Lab, of LLNL's M.E. Dept. - Material Fabrication Division, was requested to provide 250 coated Parylene target foils for a nuclear physics experiment titled the ROMANO Event. Due to the developmental nature of some of the fabrication procedures, approximately 400 coated foils were produced to satisfy the event's needs. The foils were used in the experiment as subkilovolt x-ray, narrow band pass filters, and wide band ultraviolet filters. This paper is divided into three sections describing: (1) nuclear target foil fabrication, (2) Parylene substrate preparation and production, and (3) foil and substrate inspections.

  16. Carbon stripper foils for heavy-ion accelerators

    SciTech Connect

    Thomas, G.E.

    1980-01-01

    Carbon stripper foils have for many years been successfully used with accelerators because they yield higher average charge states than gas strippers. However, with the development of heavy ion accelerators and the resulting use of heavier ions, the carbon stripper foil lifetimes are greatly reduced. Even when using the new foils changer systems, which typically contain two hundred foils or more, it becomes necessary to have frequent accelerator shutdowns for foil reloading. The rate of experiment interruption makes it clear a new approach is necessary to increase foil lifetimes. Several techniques have been tried with varying degrees of success to strengthen these foils so that they will last longer; the most successful one reported a lifetime increase of the order of a factor of 30 over foils produced in the conventional manner. Methods of producing various types of foils will be presented, a discussion will be given on theories for foil breakage, and some new ideas will be introduced for further increasing foil lifetimes.

  17. Impact of GEM foil hole geometry on GEM detector gain

    NASA Astrophysics Data System (ADS)

    Karadzhinova, A.; Nolvi, A.; Veenhof, R.; Tuominen, E.; Hæggström, E.; Kassamakov, I.

    2015-12-01

    Detailed 3D imaging of Gas Electron Multiplier (GEM) foil hole geometry was realized. Scanning White Light Interferometry was used to examine six topological parameters of GEM foil holes from both sides of the foil. To study the effect of the hole geometry on detector gain, the ANSYS and Garfield ++ software were employed to simulate the GEM detector gain on the basis of SWLI data. In particular, the effective gain in a GEM foil with equally shaped holes was studied. The real GEM foil holes exhibited a 4% lower effective gain and 6% more electrons produced near the exit electrode of the GEM foil than the design anticipated. Our results indicate that the GEM foil hole geometry affects the gain performance of GEM detectors.

  18. Composite metal foil and ceramic fabric materials

    DOEpatents

    Webb, B.J.; Antoniak, Z.I.; Prater, J.T.; DeSteese, J.G.

    1992-03-24

    The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed. 11 figs.

  19. Composite metal foil and ceramic fabric materials

    DOEpatents

    Webb, Brent J.; Antoniak, Zen I.; Prater, John T.; DeSteese, John G.

    1992-01-01

    The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed.

  20. FoilSim: Basic Aerodynamics Software Created

    NASA Technical Reports Server (NTRS)

    Peterson, Ruth A.

    1999-01-01

    FoilSim is interactive software that simulates the airflow around various shapes of airfoils. The graphical user interface, which looks more like a video game than a learning tool, captures and holds the students interest. The software is a product of NASA Lewis Research Center s Learning Technologies Project, an educational outreach initiative within the High Performance Computing and Communications Program (HPCCP).This airfoil view panel is a simulated view of a wing being tested in a wind tunnel. As students create new wing shapes by moving slider controls that change parameters, the software calculates their lift. FoilSim also displays plots of pressure or airspeed above and below the airfoil surface.

  1. Relativistic Electron Transport Through Carbon Foils

    NASA Astrophysics Data System (ADS)

    Seliger, M.; Takasi, K.; Reinhold, C. O.; Takabayashi, Y.; Ito, T.; Komaki, K.; Azuma, T.; Yamazaki, Y.; Yamazaki, Y.

    We present a theoretical study of convoy electron emission resulting from transmission of relativistic 390 MeV/amu Ar17+ ions through carbon foils of various thicknesses. Our approach is based on a Langevin equation describing the random walk of the electron initially bound to the argon nucleus and later in the continuum. The calculated spectra of ejected electrons in the forward direction exhibit clear signatures of multiple scattering and are found to be in good agreement with recent experimental data.

  2. Temperature and thermal emissivity of the surface of Neptune's satellite Triton

    NASA Technical Reports Server (NTRS)

    Nelson, Robert M.; Smythe, William D.; Wallis, Brad D.; Horn, Linda J.; Lane, Arthur L.; Mayo, Marvin J.

    1990-01-01

    Analysis of the preliminary results from the Voyager mission to the Neptune system has provided the scientific community with several methods by which the temperature of Neptune's satellite Triton may be determined. If the 37.5 K surface temperature reported by several Voyager investigations is correct, then the photometry reported by the imaging experiment on Voyager requires that Triton's surface have a remarkably low emissivity. Such a low emissivity is not required in order to explain the photometry from the photopolarimeter experiment on Voyager. A low emissivity would be inconsistent with Triton having a rough surface at the about 100-micron scale as might be expected given the active renewal processes which appear to dominate Triton's surface.

  3. A new spectrum of Triton near the time of the Voyager encounter

    NASA Technical Reports Server (NTRS)

    Grundy, William M.; Fink, Uwe

    1991-01-01

    A 5200-10,000 A spectrum of Triton that was telescopically obtained during the summer of 1989, just before the Voyager II encounter with the Neptune system, exhibits a measurable 8900 A CH4 ice absorption band. A combination of these data with those of Voyager indicates that the absorption is caused solely by Triton surface CH4 ice. A Hapke-type model for the Triton spectrum (1) sets a 20-micron lower limit on the CH4 ice's mean grain size (although it is suspected that actual grain size is closer to 100 microns), and (2) indicates that CH4 ice is widely distributed on the southern-hemisphere surface of Triton.

  4. Nucleon and triton production from nucleon-induced reactions on 7Li

    NASA Astrophysics Data System (ADS)

    Watanabe, Yukinobu; Guo, Hairui; Nagaoka, Kohei; Matsumoto, Takuma; Ogata, Kazuyuki; Yahiro, Masanobu

    2016-06-01

    Nucleon (N) and triton production from nucleon-induced reactions on 7Li at an incident energy of 14 MeV are analyzed by using three-body continuum discretized coupled channels method (CDCC), final state interaction (FSI) model, and sequential decay (SD) model. The CDCC is used to describe nucleon and triton production via breakup continuum channels, 7Li(N,N')7Li*→ t + α. Triton production from p(n) + 7Li → t + 5Li(5He) channel and nucleon production from sequential decay of the ground-state 5Li(5He) are calculated by the FSI model and the SD model, respectively. The calculated double differential cross sections for both nucleon and triton production are in good agreement with experimental ones except at relatively low nucleon emission energies.

  5. Spectroscopic determination of the phase composition and temperature of nitrogen ice on Triton

    NASA Technical Reports Server (NTRS)

    Tryka, Kimberly A.; Brown, Robert H.; Anicich, Vincent; Cruikshank, Dale P.; Owen, Tobias C.

    1993-01-01

    Laboratory spectra of the first overtone band (2.1480 microns, 4655.4 reciprocal cm) of solid nitrogen show additional structure at 2.1618 microns (4625.8 reciprocal cm) over a limited temperature range. The spectrum of Neptune's satellite Triton shows the nitrogen overtone band as well as the temperature-sensitive component. The temperature dependence of this band may be used in conjunction with ground-based observations of Triton as an independent means of determining the temperature of surface deposits of nitrogen ice. The surface temperature of Triton is found to be 38.0 +2.0 or -1.0 K, in agreement with previous temperature estimates and measurements. There is no spectral evidence for the presence of alpha-nitrogen on Triton's surface, indicating that there is less than 10 percent carbon monoxide in solid solution with the nitrogen on the surface.

  6. Spectroscopic determination of the phase composition and temperature of nitrogen ice on Triton

    NASA Astrophysics Data System (ADS)

    Tryka, K. A.; Brown, R. H.; Anicich, V.; Cruikshank, D. P.; Owen, T. C.

    1993-08-01

    Laboratory spectra of the first overtone band (2.1480 microns, 4655.4 reciprocal cm) of solid nitrogen show additional structure at 2.1618 microns (4625.8 reciprocal cm) over a limited temperature range. The spectrum of Neptune's satellite Triton shows the nitrogen overtone band as well as the temperature-sensitive component. The temperature dependence of this band may be used in conjunction with ground-based observations of Triton as an independent means of determining the temperature of surface deposits of nitrogen ice. The surface temperature of Triton is found to be 38.0 +2.0 or -1.0 K, in agreement with previous temperature estimates and measurements. There is no spectral evidence for the presence of alpha-nitrogen on Triton's surface, indicating that there is less than 10 percent carbon monoxide in solid solution with the nitrogen on the surface.

  7. Neptune's capture of its moon Triton in a binary-planet gravitational encounter.

    PubMed

    Agnor, Craig B; Hamilton, Douglas P

    2006-05-11

    Triton is Neptune's principal satellite and is by far the largest retrograde satellite in the Solar System (its mass is approximately 40 per cent greater than that of Pluto). Its inclined and circular orbit lies between a group of small inner prograde satellites and a number of exterior irregular satellites with both prograde and retrograde orbits. This unusual configuration has led to the belief that Triton originally orbited the Sun before being captured in orbit around Neptune. Existing models for its capture, however, all have significant bottlenecks that make their effectiveness doubtful. Here we report that a three-body gravitational encounter between a binary system (of approximately 10(3)-kilometre-sized bodies) and Neptune is a far more likely explanation for Triton's capture. Our model predicts that Triton was once a member of a binary with a range of plausible characteristics, including ones similar to the Pluto-Charon pair. PMID:16688170

  8. Optofluidic dye laser in a foil.

    PubMed

    Vannahme, Christoph; Christiansen, Mads Brøkner; Mappes, Timo; Kristensen, Anders

    2010-04-26

    First order distributed feedback optofluidic dye lasers embedded in a 350 microm thick TOPAS((R)) foil are demonstrated. They are designed in order to give high output pulse energies. Microfluidic channels and first order distributed feedback gratings are fabricated in parallel by thermal nanoimprint into a 100 microm foil. The channels are closed by thermal bonding with a 250 microm thick foil and filled with 5.10(-3) mol/l Pyrromethene 597 in benzyl alcohol. The fluid forms a liquid core single mode slab waveguide of 1.6 microm height on a nanostructured grating area of 0.5 x 0.5 mm(2). This results in a large gain volume. Two grating periods of 185 nm and 190 nm yield single mode laser light emission at 566 nm and 581 nm respectively. High emitted pulse energies of more than 1 microJ are reported. Stable operation for more than 25 min at 10 Hz pulse repetition rate is achieved. PMID:20588775

  9. Brazing Inconel 625 Using the Copper Foil

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Shiang; Wang, Cheng-Yen; Shiue, Ren-Kae

    2013-12-01

    Brazing Inconel 625 (IN-625) using the copper foil has been investigated in this research. The brazed joint is composed of nanosized CrNi3 precipitates and Cr/Mo/Nb/Ni quaternary compound in the Cu/Ni-rich matrix. The copper filler 50 μm in thickness is enough for the joint filling. However, the application of Cu foil 100 μm in thickness has little effect on the shear strength of the brazed joint. The specimen brazed at 1433 K (1160 °C) for 1800 seconds demonstrates the best shear strength of 470 MPa, and its fractograph is dominated by ductile dimple fracture with sliding marks. Decreasing the brazing temperature slightly decreases the shear strength of the brazed joint due to the presence of a few isolated solidification shrinkage voids smaller than 15 μm. Increasing the brazing temperature, especially for the specimen brazed at 1473 K (1200 °C), significantly deteriorates the shear strength of the joint below 260 MPa because of coalescence of isothermal solidification shrinkage voids in the joint. The Cu foil demonstrates potential in brazing IN-625 for industrial application.

  10. Microstructural Features in Aged Erbium Tritide Foils

    SciTech Connect

    Gelles, David S.; Brewer, L. N.; Kotula, Paul G.; Cowgill, Donald F.; Busick, C. C.; Snow, C. S.

    2008-01-01

    Aged erbium tritide foil specimens are found to contain five distinctly different microstructural features. The general structure was of large columnar grains of ErT2. But on a fine scale, precipitates believed to be erbium oxy-tritides and helium bubbles could be identified. The precipitate size was in the range of ~10 nm and the bubbles were of an unusual planar shape on {111} planes with an invariant thickness of ~1 nm and a diameter on the order of 10 nm. Also, an outer layer containing no fine precipitate structure and only a few helium bubbles was present on foils. This layer is best described as a denuded zone which probably grew during aging in air. Finally, large embedded Er2O3 particles were found at low density and non-uniformly distributed, but sometimes extending through the thickness of the foil. A failure mechanism allowing the helium to escape is suggested by observed cracking between bubbles closer to end of life.

  11. Optical quality assurance of GEM foils

    NASA Astrophysics Data System (ADS)

    Hildén, T.; Brücken, E.; Heino, J.; Kalliokoski, M.; Karadzhinova, A.; Lauhakangas, R.; Tuominen, E.; Turpeinen, R.

    2015-01-01

    An analysis software was developed for the high aspect ratio optical scanning system in the Detector Laboratory of the University of Helsinki and the Helsinki Institute of Physics. The system is used e.g. in the quality assurance of the GEM-TPC detectors being developed for the beam diagnostics system of the SuperFRS at future FAIR facility. The software was tested by analyzing five CERN standard GEM foils scanned with the optical scanning system. The measurement uncertainty of the diameter of the GEM holes and the pitch of the hole pattern was found to be 0.5 μm and 0.3 μm, respectively. The software design and the performance are discussed. The correlation between the GEM hole size distribution and the corresponding gain variation was studied by comparing them against a detailed gain mapping of a foil and a set of six lower precision control measurements. It can be seen that a qualitative estimation of the behavior of the local variation in gain across the GEM foil can be made based on the measured sizes of the outer and inner holes.

  12. Composition, Physical State, and Distribution of Ices at the Surface of Triton

    NASA Technical Reports Server (NTRS)

    deBergh, Catherine; Cruikshank, Dale P.; Owen, Tobias C.; Geballe, Thomas R.; Roush, Ted L.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    This paper presents the analysis of near-infrared observations of the icy surface of Triton, recorded on 1995 September 7, with the cooled grating spectrometer CGS4 at the United Kingdom Infrared Telescope (Mauna Kea, HI). This analysis was performed in two steps. The step consisted of identifying the molecules composing Triton's surface by comparing the observations with laboratory transmission spectra (direct spectral analysis ); this also gives information on the physical state of the components.

  13. Surface and airborne evidence for plumes and winds on triton.

    PubMed

    Hansen, C J; McEwen, A S; Ingersoll, A P; Terrile, R J

    1990-10-19

    Aeolian features on Triton that were imaged during the Voyager Mission have been grouped. The term "aeolian feature" is broadly defined as features produced by or blown by the wind, including surface and airborne materials. Observations of the latitudinal distributions of the features probably associated with current activity (known plumes, crescent streaks, fixed terminator clouds, and limb haze with overshoot) all occur from latitude -37 degrees to latitude -62 degrees . Likely indicators of previous activity (dark surface streaks) occur from latitude -5 degrees to -70 degrees , but are most abundant from -15 degrees to -45 degrees , generally north of currently active features. Those indicators which give information on wind direction and speed have been measured. Wind direction is a function of altitude. The predominant direction of the surface wind streaks is found to be between 40 degrees and 80 degrees measured clockwise from north. The average orientation of streaks in the northeast quadrant is 59 degrees . Winds at 1- to 3- kilometer altitude are eastward, while those at &8 kilometers blow west. PMID:17793018

  14. Stellar Occultation Studies of Pluto, Triton, Charon, and Chiron

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    2002-01-01

    Bodies inhabiting the outer solar system are of interest because, due to the colder conditions, they exhibit unique physical processes. Also, some of the lessons learned from them can be applied to understanding what occurred in the outer solar system during its formation and early evolution. The thin atmospheres of Pluto and Triton have structure that is not yet understood, and they have been predicted to undergo cataclysmic seasonal changes. Charon may have an atmosphere - we don't know. Chiron exhibits cometary activity so far from the sun (much further than most comets), so that H2O sublimation cannot be the driving mechanism. Probing these bodies from Earth with a spatial resolution of a few kilometers can be accomplished only with the stellar occultation technique. In this program we find and predict stellar occultation events by small outer-solar system bodies and then attempt observations of the ones that can potentially answer interesting questions. We also develop new methods of data analysis for occultations and secure other observations that are necessary for interpretation of the occultation data.

  15. Triton's geyser-like plumes: Discovery and basic characterization

    USGS Publications Warehouse

    Soderblom, L.A.; Kieffer, S.W.; Becker, T.L.; Brown, R.H.; Cook, A.F., II; Hansen, C.J.; Johnson, T.V.; Kirk, R.L.; Shoemaker, E.M.

    1990-01-01

    At least four active geyser-like eruptions were discovered in Voyager 2 images of Triton, Neptune's large satellite. The two best documented eruptions occur as columns of dark material rising to an altitude of about 8 kilometers where dark clouds of material are left suspended to drift downwind over 100 kilometers. The radii of the rising columns appear to be in the range of several tens of meters to a kilometer. One model for the mechanism to drive the plumes involves heating of nitrogen ice in a sub-surface greenhouse environment; nitrogen gas pressurized by the solar heating explosively vents to the surface carrying clouds of ice and dark particles into the atmosphere. A temperature increase of less than 4 kelvins above the ambient surface value of 38 ?? 3 kelvins is more than adequate to drive the plumes to an 8-kilometer altitude. The mass flux in the trailing clouds is estimated to consist of up to 10 kilograms of fine dark particles per second or twice as much nitrogen ice and perhaps several hundred or more kilograms of nitrogen gas per second. Each eruption may last a year or more, during which on the order of a tenth of a cubic kilometer of ice is sublimed.

  16. The Neptune/Triton Explorer Mission: A Concept Feasibility Study

    NASA Technical Reports Server (NTRS)

    Esper, Jaime

    2003-01-01

    Technological advances over the next 10 to 15 years promise to enable a number of smaller, more capable science missions to the outer planets. With the inception of miniaturized spacecraft for a wide range of applications, both in large clusters around Earth, and for deep space missions, NASA is currently in the process of redefining the way science is being gathered. Technologies such as 3-Dimensional Multi-Chip Modules, Micro-machined Electromechanical Devices, Multi Functional Structures, miniaturized transponders, miniaturized propulsion systems, variable emissivity thermal coatings, and artificial intelligence systems are currently in research and development, and are scheduled to fly (or have flown) in a number of missions. This study will leverage on these and other technologies in the design of a lightweight Neptune orbiter unlike any other that has been proposed to date. The Neptune/Triton Explorer (NExTEP) spacecraft uses solar electric earth gravity assist and aero capture maneuvers to achieve its intended target orbit. Either a Taurus or Delta-class launch vehicle may be used to accomplish the mission.

  17. Studies of the Gas Tori of Titan and Triton

    NASA Technical Reports Server (NTRS)

    Smyth, William H.; Marconi, M. L.

    1997-01-01

    A model for the spatial distribution of hydrogen in the Saturn system including a Titan source, an interior source for the rings and inner icy satellites, and a Saturn source has been applied to the best available Voyager 1 and 2 UVS Lyman-alpha observations presented by Shemansky and Hall. Although the model-data comparison is limited by the quality of the observational data, source rates for a Titan source of 3.3 - 4.8 x 10(exp 27) H atoms/s and, for the first time, source rates larger by about a factor of four for the interior source of 1.4 - 1.9 x 10(exp 27) H atoms/s were determined. Outside the immediate location of the planet, the Saturn source is only a minor contribution of hydrogen. A paper describing this research in more detail has been submitted to The Astrophysical Journal for publication and is included in the Appendix. Limited progress in the development of a model for the collisional gas tori of Triton is also discussed.

  18. Surface and airborne evidence for plumes and winds on Triton

    NASA Technical Reports Server (NTRS)

    Hansen, C. J.; Terrile, R. J.; Mcewen, A.; Ingersoll, A.

    1990-01-01

    Aeolian features on Triton that were imaged during the Voyager Mission have been grouped. The term 'aeolian feature' is broadly defined as features produced by or blown by the wind, including surface and airborne materials. Observations of the latitudinal distributions of the features probably associated with current activity (known plumes, crescent streaks, fixed terminator clouds, and limb haze with overshoot) all occur from latitude -37 deg to latitude -62 deg. Likely indicators of previous activity (dark surface streaks) occur from latitude -5 deg to -70 deg, but are most abundant from -15 deg to -45 deg, generally north of currently active features. Those indicators which give information on wind direction and speed have been measured. Wind direction is a function of altitude. The predominant direction of the surface wind streaks is found to be between 40 deg and 80 deg measured clockwise from north. The average orientation of streaks in the northeast quadrant is 59 deg. Winds at 1- to 3-kilometer altitude are eastward, while those at more than 8 kilometers blow west.

  19. Triton's Geyser-Like Plumes: Discovery and Basic Characterization.

    PubMed

    Soderblom, L A; Kieffer, S W; Becker, T L; Brown, R H; Cook, A F; Hansen, C J; Johnson, T V; Kirk, R L; Shoemaker, E M

    1990-10-19

    At least four active geyser-like eruptions were discovered in Voyager 2 images of Triton, Neptune's large satellite. The two best documented eruptions occur as columns of dark material rising to an altitude of about 8 kilometers where dark clouds of material are left suspended to drift downwind over 100 kilometers. The radii of the rising columns appear to be in the range of several tens of meters to a kilometer. One model for the mechanism to drive the plumes involves heating of nitrogen ice in a subsurface greenhouse environment; nitrogen gas pressurized by the solar heating explosively vents to the surface carrying clouds of ice and dark partides into the atmosphere. A temperature increase of less than 4 kelvins above the ambient surface value of 38 +/- 3 kelvins is more than adequate to drive the plumes to an 8-kilometer altitude. The mass flux in the trailing clouds is estimated to consist of up to 10 kilograms of fine dark particles per second or twice as much nitrogen ice and perhaps several hundred or more kilograms of nitrogen gas per second. Each eruption may last a year or more, during which on the order of a tenth of a cubic kilometer of ice is sublimed. PMID:17793016

  20. Nucleon-nucleon scattering contribution to the triton binding energy

    SciTech Connect

    Noyes, H.P.

    1983-04-01

    We conjectured in 1972 that much of the dynamics of a few nucleon systems could be computed from the on-shell nucleon-nucleon scatterings provided that a consistent few body theory using this input could be constructed. Such a Zero Range Scattering Theory has been shown to lead to unitary three and four particle scattering amplitudes provided only the two particle amplitudes have no singularities other than bound state poles when continued to negative energies, which restricts the theory to Castillejo-Dalitz-Dyson solutions of the Low equation. We extend the model by rewriting the off-shell amplitude which drives the Faddeev equations. This amplitude retains full off-shell unitarity and still leads to unitary on-shell three particle amplitudes. This amounts to keeping any unitary two-nucleon amplitude on-shell and restricting the analytic continuation to negative energies to the term which represents the correct continuation of the two particle total partial wave cross section; the meson exchange or potential contributions are eliminated in the unphysical region, thus excising the left-hand cut. Using this model in the zero range Faddeev equations for the three nucleon system our preliminary results show that the on-shell scatterings bind the triton with about 2.5 MeV and are insensitive to the details of the fit.

  1. New constraints on the surface properties of Triton

    NASA Astrophysics Data System (ADS)

    Merlin, Frederic; Lellouch, E.; Quirico, E.; Barucci, A.; Schmitt, B.; Perna, D.; Dumas, C.

    2014-11-01

    Triton is one of the largest satellites of the solar system and was probably captured from the transneptunian population. The global composition, size and orbit of this object lead to the formation, as in the case of Pluto, of a thin N2 rich atmosphere, with CH4 and CO traces (Lellouch et al. 2011 Msngr145 , Greaves et al.2011 RAS 414). Sublimation of these species could lead to geographical and temporal chemical variation (Grundy et al. 2010 Icarus 205) as well as the formation of complex chemical compounds mainly formed from irradiation of N2 :CH4 :CO layers (Moore and Hudson 2003 Icarus 161). Quirico et al. (1999 Icarus 139), for instance, mentioned unidentified features possibly due to the presence of such material. New observations have been obtained at the VLT-ESO with SINFONI and will be presented in order to comment on new constraints on the chemical and physical properties of the surface from H and K band spectroscopy at different longitudes. Our analyses confirm the strong longitudinal variation of N2 and CO species and indicate temporal variation too. Several models based on the Hapke theory (1981) have also been tested in order to constrain the temperature, size, abundance and state of the major ices (N2, CH4, CO, CO2 and H2O ) as well as an attempt to identify other species (NH3, C2H2, C2H6).

  2. Malignant Triton Tumors in Sisters with Clinical Neurofibromatosis Type 1

    PubMed Central

    Alina, Basnet; Sebastian, Jofre A.; Gerardo, Capo

    2015-01-01

    Malignant triton tumors (MTTs) are rare and aggressive sarcomas categorized as a subgroup of malignant peripheral nerve sheath tumors (MPNSTs). MTTs arise from Schwann cells of peripheral nerves or existing neurofibromas and have elements of rhabdomyoblastic differentiation. We report the occurrence of MTTs in two sisters. The first patient is a 36-year-old female who presented with left sided chest wall swelling. She also had clinical features consistent with neurofibromatosis type 1 (NF-1). Debulking of the mass showed high-grade malignant peripheral nerve sheath tumor with skeletal muscle differentiation (MTT). The patient was treated with ifosfamide and adriamycin along with radiation. Four years after treatment, she still has no evidence of disease recurrence. Her sister subsequently presented to us at the age of 42 with left sided lateral chest wall pain. Imaging showed a multicompartmental retroperitoneal cystic mass with left psoas involvement. The tumor was resected and, similarly to her sister, it showed high-grade malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation (MTT). The patient was started on chemotherapy and radiation as described above. PMID:26114002

  3. Utilization of Triton X-100 and polyethylene glycols during surfactant-mediated biodegradation of diesel fuel.

    PubMed

    Wyrwas, Bogdan; Chrzanowski, Łukasz; Ławniczak, Łukasz; Szulc, Alicja; Cyplik, Paweł; Białas, Wojciech; Szymański, Andrzej; Hołderna-Odachowska, Aleksandra

    2011-12-15

    The hypothesis regarding preferential biodegradation of surfactants applied for enhancement of microbial hydrocarbons degradation was studied. At first the microbial degradation of sole Triton X-100 by soil isolated hydrocarbon degrading bacterial consortium was confirmed under both full and limited aeration with nitrate as an electron acceptor. Triton X-100 (600 mg/l) was utilized twice as fast for aerobic conditions (t(1/2)=10.3h), compared to anaerobic conditions (t(1/2)=21.8h). HPLC/ESI-MS analysis revealed the preferential biodegradation trends in both components classes of commercial Triton X-100 (alkylphenol ethoxylates) as well as polyethylene glycols. The obtained results suggest that the observed changes in the degree of ethoxylation for polyethylene glycol homologues occurred as a consequence of the 'central fission' mechanism during Triton X-100 biodegradation. Subsequent experiments with Triton X-100 at approx. CMC concentration (150 mg/l) and diesel oil supported our initial hypothesis that the surfactant would become the preferred carbon source even for hydrocarbon degrading bacteria. Regardless of aeration regimes Triton X-100 was utilized within 48-72 h. Efficiency of diesel oil degradation was decreased in the presence of surfactant for aerobic conditions by approx. 25% reaching 60 instead of 80% noted for experiments without surfactant. No surfactant influence was observed for anaerobic conditions. PMID:21996621

  4. Application of triton X-100 surfactant for silicon anisotropic etching in KOH-based solutions

    NASA Astrophysics Data System (ADS)

    Rola, Krzysztof P.; Zubel, Irena

    2013-10-01

    The results of etching of silicon surfaces with different crystallographic orientations in KOH solutions containing a nonionic surfactant Triton X-100 are presented in this paper. The etch rate ratio R(100)/R(110) >1, typical of KOH + IPA and TMAH + Triton X-100 mixtures, is achieved. The surface morphology of Si( hkl) wafers is closely investigated by SEM and AFM. The very low roughness of (110) and its vicinal ( hh1) planes is observed and measured. In addition, the relatively smooth ( h11) surfaces are obtained in the solution with Triton X-100 surfactant, as compared to the KOH solutions containing alcohols. Due to good smoothness of the studied surfaces, the KOH solution with Triton X-100 seems to be especially interesting for bulk micromachining employing non-standard ( hkl) planes. The examples of mesas and trenches fabricated by anisotropic etching in the KOH solution containing Triton X-100 surfactant are presented. Keywords: silicon anisotropic etching;Triton X-100; potassium hydroxide; Si( hkl) surfaces

  5. Direct UV Spectrophotometry and HPLC Determination of Triton X-100 in Split Virus Influenza Vaccine.

    PubMed

    Pavlović, Bojana; Cvijetić, Nataša; Dragačević, Luka; Ivković, Branka; Vujić, Zorica; Kuntić, Vesna

    2016-03-01

    One of the most commonly used surfactants in the production of split virus influenza vaccine is nonionic surfactant Triton X-100. After splitting of the virus is accomplished, Triton X-100 is removed from the vaccine by subsequent production steps. Because of toxicity of Triton X-100, which remains in the vaccine in residual amounts, a sufficiently sensitive method for its detection and quantification needs to be defined. Two methods for determination of Triton X-100 residuals were developed: the UV-spectrophotometry and HPLC methods. For both methods, preparation of vaccine samples and removal of proteins and virus particles were crucial: samples were treated with methanol (1:1) and then centrifuged at 25 000 × g for 30 min. After such treatment, the majority of vaccine components that interfered in the UV region were removed, and diluted samples could be directly measured. The chromatographic system included C18 column, step methanol gradient, and detection at 225 nm with a single peak of Triton X-100 at 12.6 min. Both methods were validated and gave satisfactory results for accuracy, precision, specificity, linearity, and robustness. LOQ was slightly lower for the HPLC method. Hence, it was shown that both methods are suitable for analysis of residual amounts of Triton X-100, with the advantages of the UV method being its simplicity and availability in most laboratories. PMID:26960682

  6. Carbon stripper foils used in the Los Alamos PSR

    SciTech Connect

    Borden, M.J.; Plum, M.A.; Sugai, I.

    1997-12-01

    Carbon stripper foils produced by the modified controlled ACDC arc discharge method (mCADAD) at the Institute for Nuclear Study have been tested and used for high current 800-MeV beam production in the Proton Storage Ring (PSR) since 1993. Two foils approximately 110 {mu}g/cm{sup 2} each are sandwiched together to produce an equivalent 220 {mu}g/cm{sup 2} foil. The foil sandwitch is supported by 4-5 {mu}m diameter carbon filters attached to an aluminum frame. These foils have survived as long as five months during PSR normal beam production of near 70 {mu}A average current on target. Typical life-times of other foils vary from seven to fourteen days with lower on-target average current. Beam loss data also indicate that these foils have slower shrinkage rates than standard foils. Equipment has been assembled and used to produce foils by the mCADAD method at Los Alamos. These foils will be tested during 1997 operation.

  7. Foil changer for the Chalk River superconducting cyclotron

    SciTech Connect

    Hoffmann, C.R.; Kilborn, R.I.; Mouris, J.E.; Proulx, D.R.; Weaver, J.F.

    1985-10-01

    Capture of an injected beam in the Chalk River superconducting cyclotron requires that a carbon stripping foil be accurately placed in a dee to intercept the incoming beam. Foil radial position must be precisely adjustable and foils must be easily replaced. A foil changing apparatus has been designed, built and tested to meet these requirements. The main components are a supply magazine, a transport system, and unloading and loading mechanisms. The magazine is on top of the cyclotron. It holds 300 foils and can be isolated from machine vacuum for refilling. Each foil is mounted on a stainless steel frame. A stainless steel roller chain fitted with 33 copper sleeves (shrouds) carries foils, one per shroud, down a dee stem to the midplane. A 12-bit absolute optical shaft encoder senses foil position. To replace a foil a shroud is positioned at the top of the cyclotron, a foil is removed, and another is transferred from the magazine to the empty shroud. Three stepping motors and associated electronics provide mechanical drive and are interfaced with a CAMAC control system.

  8. The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2001-01-01

    Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30,000 rpm and at 25 C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120% when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40% against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.

  9. Aerocapture Performance Analysis for a Neptune-Triton Exploration Mission

    NASA Technical Reports Server (NTRS)

    Starr, Brett R.; Westhelle, Carlos H.; Masciarelli, James P.

    2004-01-01

    A systems analysis has been conducted for a Neptune-Triton Exploration Mission in which aerocapture is used to capture a spacecraft at Neptune. Aerocapture uses aerodynamic drag instead of propulsion to decelerate from the interplanetary approach trajectory to a captured orbit during a single pass through the atmosphere. After capture, propulsion is used to move the spacecraft from the initial captured orbit to the desired science orbit. A preliminary assessment identified that a spacecraft with a lift to drag ratio of 0.8 was required for aerocapture. Performance analyses of the 0.8 L/D vehicle were performed using a high fidelity flight simulation within a Monte Carlo executive to determine mission success statistics. The simulation was the Program to Optimize Simulated Trajectories (POST) modified to include Neptune specific atmospheric and planet models, spacecraft aerodynamic characteristics, and interplanetary trajectory models. To these were added autonomous guidance and pseudo flight controller models. The Monte Carlo analyses incorporated approach trajectory delivery errors, aerodynamic characteristics uncertainties, and atmospheric density variations. Monte Carlo analyses were performed for a reference set of uncertainties and sets of uncertainties modified to produce increased and reduced atmospheric variability. For the reference uncertainties, the 0.8 L/D flatbottom ellipsled vehicle achieves 100% successful capture and has a 99.87 probability of attaining the science orbit with a 360 m/s V budget for apoapsis and periapsis adjustment. Monte Carlo analyses were also performed for a guidance system that modulates both bank angle and angle of attack with the reference set of uncertainties. An alpha and bank modulation guidance system reduces the 99.87 percentile DELTA V 173 m/s (48%) to 187 m/s for the reference set of uncertainties.

  10. Effects of Aluminum Foil Packaging on Elemental Analysis of Bone.

    PubMed

    Lewis, Lyniece; Christensen, Angi M

    2016-03-01

    Burned skeletal material is often very fragile and at high risk for fragmentation during packaging and transportation. One method that has been suggested to protect bones in these cases is to carefully wrap them in aluminum foil. Traces of aluminum, however, are known to transfer from foil packaging materials to food products. If such transfer occurs between aluminum foil and bones, it could interfere with subsequent chemical, elemental and isotopic analyses, which are becoming more common in forensic anthropological investigations. This study examined aluminum levels in bones prior to and following the use of aluminum foil packaging and storage for a 6-week period. Results indicate no significant change in the detected levels of aluminum (p > 0.05), even when packaged in compromised foil and exposed to elevated temperatures. Aluminum foil can therefore continue to be recommended as a packaging medium without affecting subsequent chemical examinations. PMID:27404616

  11. Microfabricated Segmented-Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

    2010-01-01

    An involute-foil regenerator was designed, microfabricated, and tested in an oscillating-flow test rig. The concept consists of stacked involute-foil nickel disks (see figure) microfabricated via a lithographic process. Test results yielded a performance of about twice that of the 90-percent random-fiber currently used in small Stirling converters. The segmented nature of the involute- foil in both the axial and radial directions increases the strength of the structure relative to wrapped foils. In addition, relative to random-fiber regenerators, the involute-foil has a reduced pressure drop, and is expected to be less susceptible to the release of metal fragments into the working space, thus increasing reliability. The prototype nickel involute-foil regenerator was adequate for testing in an engine with a 650 C hot-end temperature. This is lower than that required by larger engines, and high-temperature alloys are not suited for the lithographic microfabrication approach.

  12. Method of forming a thin unbacked metal foil

    DOEpatents

    Duchane, David V.; Barthell, Barry L.

    1984-01-01

    In a method of forming a thin (<2 .mu.m) unbacked metal foil having a desired curviplanar shape, a soluble polymeric film, preferably comprising polyvinyl alcohol, is formed on a supporting structure having a shape that defines the desired shape of the foil product. A layer of metal foil is deposited onto one side of the soluble film, preferably by vacuum vapor deposition. The metallized film is then immersed in a suitable solvent to dissolve the film and thereby leave the metal foil as an unbacked metal foil element mounted on the supporting structure. Aluminum foils less than 0.2 .mu.m (2,000 .ANG.) thick and having an areal density of less than 54 .mu.g/cm.sup.2 have been obtained.

  13. Dynamics of a satellite and normalization around lagrangian points in the Neptune-Triton system

    NASA Astrophysics Data System (ADS)

    Yokoyama, T.; Stuchi, T. J.; Solórzano, C. R. H.; Corria, A. A.; Prado, A. F. B.; Winter, O. C.; Winter, S. M. G.; Sanchez, D. M.

    Since a mission to Pluto-Charon is in progress a similar mission to Neptune-Triton system probably is just a matter of time Besides the interesting items listed in the Hammel s proposal to explore Neptune Hammel et al 2002 there are others very interesting points Triton is a very large satellite with M T M N approx 2 09 times 10 -4 where M T and M N are the masses of Triton and Neptune respectively Its current inclination with respect to Neptune s equator is about 157 345 0 This unusual high and retrograde inclination for a very large inner satellite makes this problem unique in our solar system Hammel et al 2002 also propose that a top priority in this mission should be a Neptune-Triton orbiter not just a flyby tour Therefore assuming a massless spacecraft orbiting Neptune-Triton system basically the system can be stated in terms of the classical restricted three body problem The new ingredient is the Neptune oblateness and the retrograde motion of Triton With some slight displacements the lagrangian equilibria points still exist as well as many of the properties of the classical problem In this work we first give an extensive numerical exploration in the case when the spacecraft orbits Triton considering Sun Neptune and its oblateness as disturbers In the plane bf a times bf I where bf a is the semi major axis and bf I is the inclination of the orbiter we give a plot of the stable regions where the massless can survive for thousand of years Retrograde and direct inclinations were

  14. Magnetohydrodynamic modelling of exploding foil initiators

    NASA Astrophysics Data System (ADS)

    Neal, William

    2015-06-01

    Magnetohydrodynamic (MHD) codes are currently being developed, and used, to predict the behaviour of electrically-driven flyer-plates. These codes are of particular interest to the design of exploding foil initiator (EFI) detonators but there is a distinct lack of comparison with high-fidelity experimental data. This study aims to compare a MHD code with a collection of temporally and spatially resolved diagnostics including PDV, dual-axis imaging and streak imaging. The results show the code's excellent representation of the flyer-plate launch and highlight features within the experiment that the model fails to capture.

  15. Apparatus and process for ultrasonic seam welding stainless steel foils

    DOEpatents

    Leigh, Richard W.

    1992-01-01

    An ultrasonic seam welding apparatus having a head which is rotated to form contact, preferably rolling contact, between a metallurgically inert coated surface of the head and an outside foil of a plurality of layered foils or work materials. The head is vibrated at an ultrasonic frequency, preferably along a longitudinal axis of the head. The head is constructed to transmit vibration through a contacting surface of the head into each of the layered foils. The contacting surface of the head is preferably coated with aluminum oxide to prevent the head from becoming welded to layered stainless steel foils.

  16. [Foil bandages--a modern method of covering wounds].

    PubMed

    Sedlarik, K M; Hájek, M

    1994-04-01

    Single-layer foil bandages which belong to the group of so-called occlusive bandaging materials were originally developed from incision foils. Due to their semipermeability theses bandages permit only restricted evaporation of water from the wound and thus maintain its surface constantly slightly wet. They can be used for longer periods and are thus more economical. Although foil bandages are suitable only for some types of wounds, they have great advantages. Wounds dressed with these foil bandages can be easily and frequently checked and offer wounds excellent antimicrobial protection. PMID:8085186

  17. Characterization of U-Mo Foils for AFIP-7

    SciTech Connect

    Edwards, Danny J.; Ermi, Ruby M.; Schemer-Kohrn, Alan L.; Overman, Nicole R.; Henager, Charles H.; Burkes, Douglas; Senor, David J.

    2012-11-07

    Twelve AFIP in-process foil samples, fabricated by either Y-12 or LANL, were shipped from LANL to PNNL for potential characterization using optical and scanning electron microscopy techniques. Of these twelve, nine different conditions were examined to one degree or another using both techniques. For this report a complete description of the results are provided for one archive foil from each source of material, and one unirradiated piece of a foil of each source that was irradiated in the Advanced Test Reactor. Additional data from two other LANL conditions are summarized in very brief form in an appendix. The characterization revealed that all four characterized conditions contained a cold worked microstructure to different degrees. The Y-12 foils exhibited a higher degree of cold working compared to the LANL foils, as evidenced by the highly elongated and obscure U-Mo grain structure present in each foil. The longitudinal orientations for both of the Y-12 foils possesses a highly laminar appearance with such a distorted grain structure that it was very difficult to even offer a range of grain sizes. The U-Mo grain structure of the LANL foils, by comparison, consisted of a more easily discernible grain structure with a mix of equiaxed and elongated grains. Both materials have an inhomogenous grain structure in that all of the characterized foils possess abnormally coarse grains.

  18. Methods of making metallic glass foil laminate composites

    DOEpatents

    Vianco, Paul T.; Fisher, Robert W.; Hosking, Floyd M.; Zanner, Frank J.

    1996-01-01

    A process for the fabrication of a rapidly solidified foil laminate composite. An amorphous metallic glass foil is flux treated and coated with solder. Before solidification of the solder the foil is collected on a take-up spool which forms the composite into a solid annular configuration. The resulting composite exhibits high strength, resiliency and favorable magnetic and electrical properties associated with amorphous materials. The composite also exhibits bonding strength between the foil layers which significantly exceeds the bulk strength of the solder alone.

  19. Methods of making metallic glass foil laminate composites

    DOEpatents

    Vianco, P.T.; Fisher, R.W.; Hosking, F.M.; Zanner, F.J.

    1996-08-20

    A process for the fabrication of a rapidly solidified foil laminate composite. An amorphous metallic glass foil is flux treated and coated with solder. Before solidification of the solder the foil is collected on a take-up spool which forms the composite into a solid annular configuration. The resulting composite exhibits high strength, resiliency and favorable magnetic and electrical properties associated with amorphous materials. The composite also exhibits bonding strength between the foil layers which significantly exceeds the bulk strength of the solder alone. 6 figs.

  20. Mounting stripper foils on forks for maximum lifetime

    NASA Astrophysics Data System (ADS)

    Jolivet, Connie S.; Stoner, John O.

    2008-06-01

    While research and development continue to produce forms of carbon for longer lasting stripper foils, relatively little attention has been paid to other factors that affect their survival in use. It becomes apparent that the form of carbon is only part of the issue. Specific mounting methods increase the lifetimes of carbon stripper foils. These methods are determined in part by the specific use and carbon type for a foil. With careful handling, appropriate adhesive, and slack mounting, premature breakage can be avoided. Foil lifetimes are then primarily affected by less easily controlled factors such as high-temperature expansion, shrinkage and evaporation.

  1. SNS STRIPPER FOIL FAILURE MODES AND THEIR CURES

    SciTech Connect

    Galambos, John D; Luck, Chris; Plum, Michael A; Shaw, Robert W; Ladd, Peter; Raparia, Deepak; Macek, Robert James; Kim, Sang-Ho; Peters, Charles C; Polsky, Yarom

    2010-01-01

    The diamond stripper foils in use at the Spallation Neutron Source worked successfully with no failures until May 3, 2009, when we started experiencing a rash of foil system failures after increasing the beam power to ~840 kW. The main contributors to the failures are thought to be 1) convoy electrons, stripped from the incoming H beam, that strike the foil bracket and may also reflect back from the electron catcher, and 2) vacuum breakdown from the charge developed on the foil by secondary electron emission. In this paper we will detail these and other failure mechanisms, and describe the improvements we have made to mitigate them.

  2. Ti foil light in the ATA (Advanced Test Accelerator) beam

    SciTech Connect

    Slaughter, D.R.; Chong, Y.P.; Goosman, D.R.; Rule, D.W.; Fiorito, R.B.

    1987-09-01

    An experiment is in progress to characterize the visible light produced when a Ti foil is immersed in the ATA 2 kA, 43 MeV beam. Results obtained to date indicate that the optical condition of the foil surface is a critical determinant of these characteristics, with a very narrow angular distribution obtained when a highly polished and flat foil is used. These data are consistent with the present hypothesis that the light is produced by transition radiation. Incomplete experiments to determine the foil angle dependence of the detected light and its polarization are summarized and remaining experiments are described.

  3. Complexation of serum albumins and triton X-100: Quenching of tryptophan fluorescence and analysis of the rotational diffusion of complexes

    NASA Astrophysics Data System (ADS)

    Vlasova, I. M.; Vlasov, A. A.; Saletskii, A. M.

    2016-07-01

    The polarized and nonpolarized fluorescence of bovine serum albumin and human serum albumin in Triton X-100 solutions is studied at different pH values. Analysis of the constants of fluorescence quenching for BSA and HSA after adding Triton X-100 and the hydrodynamic radii of BSA/HSA-detergent complexes show that the most effective complexation between both serum albumins and Triton X-100 occurs at pH 5.0, which lies near the isoelectric points of the proteins. Complexation between albumin and Triton X-100 affects the fluorescence of the Trp-214 residing in the hydrophobic pockets of both BSA and HSA.

  4. Method of making porous conductive supports for electrodes. [by electroforming and stacking nickel foils

    NASA Technical Reports Server (NTRS)

    Schaer, G. R. (Inventor)

    1973-01-01

    Porous conductive supports for electrochemical cell electrodes are made by electroforming thin corrugated nickel foil, and by stacking pieces of the corrugated foil alternatively with pieces of thin flat nickel foil. Corrugations in successive corrugated pieces are oriented at different angles. Adjacent pieces of foil are bonded by heating in a hydrogen atmosphere and then cutting the stack in planes perpendicular to the foils.

  5. Infrared spectoscopy of Triton and Pluto ice analogs: The case for saturated hydrocarbons

    NASA Technical Reports Server (NTRS)

    Bohn, Robert B.; Sandford, Scott A.; Allamandola, Louis J.; Cruikshank, Dale P.

    1994-01-01

    The infrared transmission spectra and photochemical behavior of various organic compounds isolated in solid N2 ices, appropriate for applications to Triton ad Pluto, are presented. It is shown that excess absorption in the surface spectra of Triton and Pluto, i.e., absorption not explained by present models incorporating molecules already identified on these bodies (N2, CH4, CO, and CO2), that starts near 4450/cm (2.25 microns) and extends to lower frequencies, may be due to alkanes (C(n)H(2n+2)) and related molecules frozen in the nitrogen. Branched and linear alkanes may be responsible. Experiments in which the photochemstry of N2: CH4 and N2: CH4: CO ices was explored demonsrtrate that the surface ices of Triton and Pluto may contain a wide variety of additional species containing H, C, O, and N. Of these, the reactive molecule diazomethane, CH2N2, is particularly important since it may be largely responsible for the synthesis of larger alkanes from CH4 and other small alkanes. Diazomethane would also be expected to drive chemical reactions involving organics in the surface ices of Triton and Pluto toward saturation, i.e., to reduce multiple CC bonds. The positions and intrinsic strengths (A values) of many of the infrared absorption bands of N2 matrix-isolated molecules of relevance to Triton and Pluto have also been determined. These can be used to aid in their search and to place constraints on their abundances.

  6. Zonally averaged thermal balance and stability models for nitrogen polar caps on Triton

    NASA Technical Reports Server (NTRS)

    Stansberry, John A.; Lunine, J. I.; Porco, C. C.; Mcewen, A. S.

    1990-01-01

    Voyager four-color imaging data of Triton are analyzed to calculate the bolometric hemispheric albedo as a function of latitude and longitude. Zonal averages of these data have been incorporated into a thermal balance model involving insolation, reradiation, and latent heat of sublimation of N2 ice for the surface. The current average bolometric albedo of Triton's polar caps is 0.8, implying an effective temperature of 34.2 K and a surface pressure of N2 of 1.6 microbar for unit emissivity. This pressure is an order of magnitude lower than the surface pressure of 18 microbar inferred from Voyager data (Broadfoot et al., 1989; Conrath et al., 1989), a discrepancy that can be reconciled if the emissivity of the N2 on Triton's surface is 0.66. The model predicts that Triton's surface north of 15 deg N latitude is experiencing deposition of N2 frosts, as are the bright portions of the south polar cap near the equator. This result explains why the south cap covers nearly the entire southern hemisphere of Triton.

  7. Shape-controlled synthesis of Cu2O nanocrystals assisted by Triton X-100

    NASA Astrophysics Data System (ADS)

    Luo, Fang; Wu, Di; Gao, Lei; Lian, Suoyuan; Wang, Enbo; Kang, Zhenhui; Lan, Yang; Xu, Lin

    2005-12-01

    Cuprous oxide (Cu2O) nanocrystals with tubular, cubic and hollow cubic morphologies were obtained in simple solution-phase reduction systems using nonionic surfactant octylphenyl ether (Triton X-100) as solvent. Uniform single crystal nanotubes with outer diameters of ˜20 nm, inner diameters of ˜10 nm and lengths of ˜120 nm were prepared through reduction of CuCl2 by glucose. When a little amount of water was dispersed into Triton X-100, uniform cube-shaped polycrystals with edge lengths of ˜180 nm were synthesized, with ascorbic acid as the reducing agent. The water cores formed by surrounded Triton X-100 molecules with hydrophilic heads immersed provided the reaction rooms. With the help of ethanol introduced into water cores by Triton X-100 molecules, Cu2O nanocubes turned to hollow cubes with edge lengths of ˜200 nm during the ripening process. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) were used to investigate the different morphologies of the as-synthesized products. X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) were applied to characterize the composition and crystal phases of the products. It was proposed that molecules and molecule assemblies of Triton X-100 played different roles in the shape-controlled synthesis process, which were realized by carefully controlling the experiment conditions.

  8. Actinide Foil Production for MPACT Research

    SciTech Connect

    Beller, Denis

    2012-10-30

    Sensitive fast-neutron detectors are required for use in lead slowing down spectrometry (LSDS), an active interrogation technique for used nuclear fuel assay for Materials Protection, Accounting, and Controls Technologies (MPACT). During the past several years UNLV sponsored a research project at RPI to investigate LSDS; began development of fission chamber detectors for use in LSDS experiments in collaboration with INL, LANL, and Oregon State U.; and participated in a LSDS experiment at LANL. In the LSDS technique, research has demonstrated that these fission chamber detectors must be sensitive to fission energy neutrons but insensitive to thermal-energy neutrons. Because most systems are highly sensitive to large thermal neutron populations due to the well-known large thermal cross section of 235U, even a miniscule amount of this isotope in a fission chamber will overwhelm the small population of higher-energy neutrons. Thus, fast-fission chamber detectors must be fabricated with highly depleted uranium (DU) or ultra-pure thorium (Th), which is about half as efficient as DU. Previous research conducted at RPI demonstrated that the required purity of DU for assay of used nuclear fuel using LSDS is less than 4 ppm 235U, material that until recently was not available in the U.S. In 2009 the PI purchased 3 grams of ultra-depleted uranium (uDU, 99.99998% 238U with just 0.2 ± 0.1 ppm 235U) from VNIIEF in Sarov, Russia. We received the material in the form of U3O8 powder in August of 2009, and verified its purity and depletion in a FY10 MPACT collaboration project. In addition, chemical processing for use in FC R&D was initiated, fission chamber detectors and a scanning alpha-particle spectrometer were developed, and foils were used in a preliminary LSDS experiment at a LANL/LANSCE in Sept. of 2010. The as-received U3O8 powder must be chemically processed to convert it to another chemical form while maintaining its purity, which then must be used to electro-deposit U

  9. A Preliminary Investigation of Aerogravity Assist at Triton for Capture into Orbit About Neptune

    NASA Technical Reports Server (NTRS)

    Ramsey, Philip; Lyne, James Evans

    2005-01-01

    Previous work by our group has shown that an aerogravity assist maneuver at the moon Triton might be used to capture a spacecraft into a closed orbit about Neptune if a nominal atmospheric density profile at Triton is assumed. The present study extends that work and examines the impact of atmospheric dispersions, especially important in light of the very low density and large degree of uncertainty of Triton s atmosphere. Additional variables that are analyzed in the current study include ballute size and cut time and variations in the final target orbit. Results indicate that while blunt-body, rigid aeroshells penetrate too closely to the surface to be practical, ballutes of modest size show promise for this maneuver. Future studies will examine the application of inflatable aeroshells and rigid aeroshells with higher lift-to-drag ratios such as biconics and lifting bodies.

  10. DIRECT DETECTION OF SEASONAL CHANGES ON TRITON WITH HUBBLE SPACE TELESCOPE

    SciTech Connect

    Bauer, James M.; Buratti, Bonnie J.; Mosher, Joel A.; Hicks, Michael D.; Goguen, Jay D.; Li Jianyang; Schmidt, Britney E. E-mail: Bonnie.Buratti@jpl.nasa.go E-mail: hicksm@scn.jpl.nasa.go E-mail: jyli@astro.umd.ed

    2010-11-01

    Triton is one of the few bodies in the solar system with observed cryo-volcanic activity, in the form of plumes at its south pole, which suggests large-scale surface volatile transport over time. Triton's large variations in obliquity have motivated prior predictions of changing atmospheric column densities of several orders of magnitude, driven by seasonal evaporation of surface volatiles. Using the Hubble Space Telescope, we directly imaged Triton's surface and have detected large-scale differences in increased and decreased reflectance when compared with Voyager data at UV, visual, and methane-band wavelengths. Our surface map shows regions of increased brightness at near-equatorial latitudes and near the Neptune-facing side, and darkened regions near longitudes of {+-}180{sup 0}, indicating the presence of ongoing seasonal volatile transport.

  11. Tailoring Dispersion and Interaction of MWNT in Polymer Nanocomposites, Using Triton X-100 as Nonionic Surfactant

    NASA Astrophysics Data System (ADS)

    Pandey, Priyanka; Mohanty, Smita; Nayak, Sanjay K.

    2014-12-01

    This study reports an investigation on the effect of non-ionic surfactant (Triton X-100) on the dispersion of multiwalled carbon nanotubes (MWNTs) inside the polymer matrix. Adsorption of triton X-100 to the MWNTs was confirmed through FTIR. A reduced bundling of MWNT fibrils were noticed in Triton X-100 modified MWNTs (Tr-MWNTs). The polymer nanocomposites were prepared via melt blending technique. The optimization of loading ratio of the MWNTs and Tr-MWNTs was carried out on the basis of mechanical properties. Dynamic mechanical analysis exhibited the much uniform dispersion of the Tr-MWNT inside polymer matrix as compared to that of MWNTs. A faster rate of crystallization was noticed in case of MWNT reinforced nanocomposites, however, a strong filler-polymer interaction could be seen in case of Tr-MWNT filled nanocomposites. Optical microscopic analysis exhibited similar effect of MWNT and Tr-MWNT on the spherulite size of the polymer.

  12. A photochemical study of uranyl ion interaction with the Triton X-100 micellar system

    SciTech Connect

    Das, S.K.; Ganguly, B.N.

    1996-06-25

    This is a report on the spectroscopic characteristics of UO{sub 2}{sup 2+} in the excited state in Triton X-100 micellar medium. It also indicates some important results of viscosity and surface tension measurements of the system which have direct relevance to the spectroscopic investigation in the excited state. The quenching of the UO{sub 2}{sup 2+} fluorescence due to Triton X-100, upon micellization in the aqueous medium, reveals two kinds of microenvironments of the fluorophore from the Stern-Volmer plot. This has been verified by flash photolytic measurements. A blue shift of the quenched emission spectrum is ascribed to the collisional encounter of UO{sub 2}1{sub +} with the head groups of Triton X-100.

  13. Gas Foil Bearing Misalignment and Unbalance Effects

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2008-01-01

    The effects of misalignment and unbalance on gas foil bearings are presented. The future of U.S. space exploration includes plans to conduct science missions aboard space vehicles, return humans to the Moon, and place humans on Mars. All of these endeavors are of long duration, and require high amounts of electrical power for propulsion, life support, mission operations, etc. One potential source of electrical power of sufficient magnitude and duration is a nuclear-fission-based system. The system architecture would consist of a nuclear reactor heat source with the resulting thermal energy converted to electrical energy through a dynamic power conversion and heat rejection system. Various types of power conversion systems can be utilized, but the Closed Brayton Cycle (CBC) turboalternator is one of the leading candidates. In the CBC, an inert gas heated by the reactor drives a turboalternator, rejects excess heat to space through a heat exchanger, and returns to the reactor in a closed loop configuration. The use of the CBC for space power and propulsion is described in more detail in the literature (Mason, 2003). In the CBC system just described, the process fluid is a high pressure inert gas such as argon, krypton, or a helium-xenon mixture. Due to the closed loop nature of the system and the associated potential for damage to components in the system, contamination of the working fluid is intolerable. Since a potential source of contamination is the lubricant used in conventional turbomachinery bearings, Gas Foil Bearings (GFB) have high potential for the rotor support system. GFBs are compliant, hydrodynamic journal and thrust bearings that use a gas, such as the CBC working fluid, as their lubricant. Thus, GFBs eliminate the possibility of contamination due to lubricant leaks into the closed loop system. Gas foil bearings are currently used in many commercial applications, both terrestrial and aerospace. Aircraft Air Cycle Machines (ACMs) and ground

  14. Fabrication of stainless steel foil utilizing chromized steel strip

    NASA Astrophysics Data System (ADS)

    Loria, Edward A.

    1980-10-01

    Stainless steel foil has properties which are, in many respects, unmatched by alternative thin films. The high strength to weight ratio and resistance to corrosion and oxidation at elevated temperatures are generally advantageous. The aerospace and automotive industries have used Type 430 and 304 foil in turbine engine applications. Foil around 2 mils (5.1 × 10-3 cm) thick has been appropriate for the recuperator or heat exchanger and this product has also been used in honeycomb and truss-core structures. Further, such foil has been employed as a wrap to protect tool steel parts from contamination during heat treating. A large part of the high cost of producing stainless steel foil by rolling is due to the complicated and expensive rolling mill and annealing equipment involved. A method will be described which produces (solid) stainless steel foil from chromized (coated) steel which can be cheaper than the conventional processing stainless steel, such as Type 430, from ingot to foil. Also, the material is more ductile and less work hardenable during processing to foil and consequently intermediate annealing treatments are eliminated and scrap losses minimized.

  15. Foil fabrication for the ROMANO event. Revision 1

    SciTech Connect

    Romo, J.G. Jr.; Weed, J.W.; Griggs, G.E.; Brown, T.G.; Tassano, P.L.

    1984-06-13

    The Vacuum Processes Lab (VPL), of LLNL's M.E. Dept. - Material Fabrication Division (MFD), conducted various vacuum related support activities for the ROMANO nuclear physics experiment. This report focuses on the foil fabrication activities carried out between July and November 1983 for the ROMANO event. Other vacuum related activities for ROMANO, such as outgassing tests of materials, are covered in separate documentation. VPL was asked to provide 270 coated Parylene foils for the ROMANO event. However, due to the developmental nature of some of the procedures, approximately 400 coated foils were processed. In addition, VPL interacted with MFD's Plastics Shop to help supply Parylene substrates to other organizations (i.e., LBL and commercial vendors) which had also been asked to provide coated foils for ROMANO. The purposes of this report are (A) to document the processes developed and the techniques used to produce the foils, and (B) to suggest future directions. The report is divided into four sections describing: (1) nuclear target foil fabrication, (2) Parylene substrate preparation and production, (3) calibration foil fabrication, and (4) foil and substrate inspections.

  16. Insulating effectiveness of self-spacing dimpled foil

    NASA Technical Reports Server (NTRS)

    Bond, J. A.

    1972-01-01

    Experimental data are graphed for determining conductive heat losses of multilayer insulation as function of number of foil layers. Foil was 0.0051 cm thick Nb, 1% Zr refractory alloy, dimpled to 0.0254 cm with approximately 28 dimples/sq cm. Heat losses were determined at 0.1 microtorr between 700 and 1089 K.

  17. Process for producing molybdenum foil and collapsible tubing

    NASA Technical Reports Server (NTRS)

    Bretts, G. R.; Gavert, R. B.; Groschke, G. F.

    1971-01-01

    Manufacturing process produces molybdenum foil 0.002 cm thick and 305 m long, and forms foil into high-strength, thin-walled tubing which can be flattened for storage on a spool. Desirable metal properties include high thermal conductivity stiffness, yield and tensile stress, and low thermal expansion coeffecient.

  18. Haemoglobin-Triton X-100 conjugate as model system for red blood cell lysis

    NASA Astrophysics Data System (ADS)

    Pop, Simona-Florentina; Ion, Rodica-Mariana; Doncea, Sanda

    2010-11-01

    The action of detergents is thought to be connected primarily with micelle formation. However, detergent monomers can also affect biological systems. It was found that human red blood cells can be disintegrated with Triton X-100 non-ionic detergent at a concentration of 0.007%, lower than the critical micellar concentration (CMC). The lytic membrane of non-ionic detergent Triton X-100 (as a model), and its ability to lyse red blood cells in vitro used as an indicator of conjugate conformation at different pHs. The time dependent release of hemoglobin (Hb) and potassium from red blood cells was detected at 37 °C and both were sigmoid in character. Although Triton X-100 was highly lytic at pH 5.5, 7.4 and 8.0, the conjugate only show a lysis concentration-dependent of red blood cell at pH 5.5. Triton X-100 causes the Hb to aggregate, a condition that can be simulated when this non-ionic surfactant is incubated with Hb in vitro. The determination of Triton-X was done by HPLC, in accordance to characterize the surfactant. The increased stability in micellar medium can be attributed to deep penetration with the polar group -OH oriented towarded to the micelle surface. Thermal stability of hemoglobin has been investigated in order to evaluate the nature of thermal behavior of this compound. We studied the effects of surfactant Triton -X on the rate constants for the destroying of hemoglobin.

  19. Dynamic responses of a two-dimensional flapping foil motion

    NASA Astrophysics Data System (ADS)

    Lu, Xi-Yun; Liao, Qin

    2006-09-01

    The investigation of a flapping foil, which is used as a basic mode of the flapping-based locomotion in insects, birds, and fish, is performed by solving the Navier-Stokes equations numerically. In this Brief Communication we provide insight into the understanding of dynamics of a flapping foil. A critical flapping Reynolds number based on the flapping frequency and amplitude, above which a forward flapping movement occurs, is predicted. The dynamics of the flapping foil are analyzed in two dynamic responses, i.e., an oscillatory movement and a steady movement, which depend on the density ratio between the foil and the surrounded fluid. The steady movement response is related to the forward flapping motion. The Strouhal number that governs a vortex shedding for the forward flapping foil is calculated and lies in the range where flying and swimming animals will be likely to tune for high propulsive efficiency.

  20. Freezing enhancement around a horizontal tube using copper foil disks

    NASA Astrophysics Data System (ADS)

    Sugawara, M.; Komatsu, Y.; Takahashi, Y.; Beer, H.

    2011-12-01

    Freezing of water saturated in circumferentially arranged copper foils around a cooling tube is studied experimentally and numerically. The copper foils need not to be welded to the cooling tube but are merely placed around the tube so that the freezing system is easily arranged. Copper foils greatly enhance freezing compared with that of a bare tube, even with a small copper volume fraction in the freezing system. Numerical calculations by means of a continuum model predict well freezing enhancement. The effect of the copper foils is also considered numerically for the melting process in order to compare with freezing. It is seen that copper foils contribute more to the melting enhancement than to the increase of the freezing rate.

  1. Tubular hydrogen permeable metal foil membrane and method of fabrication

    DOEpatents

    Paglieri, Stephen N.; Birdsell, Stephen A.; Barbero, Robert S.; Snow, Ronny C.; Smith, Frank M.

    2006-04-04

    A tubular hydrogen permeable metal membrane and fabrication process comprises obtaining a metal alloy foil having two surfaces, coating the surfaces with a metal or metal alloy catalytic layer to produce a hydrogen permeable metal membrane, sizing the membrane into a sheet with two long edges, wrapping the membrane around an elongated expandable rod with the two long edges aligned and overlapping to facilitate welding of the two together, placing the foil wrapped rod into a surrounding fixture housing with the two aligned and overlapping foil edges accessible through an elongated aperture in the surrounding fixture housing, expanding the elongated expandable rod within the surrounding fixture housing to tighten the foil about the expanded rod, welding the two long overlapping foil edges to one another generating a tubular membrane, and removing the tubular membrane from within the surrounding fixture housing and the expandable rod from with the tubular membrane.

  2. The Prediction and Observation of the 1997 July 18 Stellar Occultation by Triton: More Evidence for Distortion and Increasing Pressure in Triton's Atmosphere

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Person, M. J.; McDonald, S. W.; Buie, M. W.; Dunham, E. W.; Millis, R. L.; Nye, R. A.; Olkin, C. B.; Wasserman, L. H.; Young, L. A.

    2000-01-01

    We used CCD (charge coupled device) astrometric data to predict where the occultation path of the star Tr 176 was located, on July 18, 1997. It could be seen from northern Australia and the southern section of North America. We set up an array of portable and mixed telescopes which had high-speed photometric equipment to observe the occultation. Goals included the following: (1) mapping the central flash; (2) obtaining light curves for the signal-to-noise ratio; (3) acquiring light curves from Triton's disk. We combined these with data from others to find the radius and geometry of the half-light surface of the atmosphere, as well as the equivalent-isothermal temperature latitudes below the occultation on Triton.

  3. [The use of prasugrel in STEMI and NSTEMI: TRITON TIMI 38 study and subgroup analyses].

    PubMed

    Abaci, Adnan

    2015-10-01

    Prasugrel, a third generation P2Y12 receptor inhibitor, is more powerful than clopidogrel. TRITON-TIMI 38 trial compared the effectiveness of prasugrel with clopidogrel in patients with STEMI and NSTEMI. This paper examined the main TRITON-TIMI 38 trial and subgroup analyses of the trial to determine patient subgroups in which prasugrel is superior to clopidogrel in preventing clinical events without an additional increase in bleeding risk. In such patients, one might expect to derive optimal benefit from prasugrel without a significant increase in bleeding. PMID:27326444

  4. Large-area beryllium metal foils

    NASA Astrophysics Data System (ADS)

    Stoner, J. O., Jr.

    1997-02-01

    To manufacture beryllium filters having diameters up to 82 mm and thicknesses in the range 0.1-1 μm, it was necessary to construct apparatus in which the metal could safely be evaporated, and then to find an acceptable substrate and evaporation procedure. The metal was evaporated resistively from a tantalum dimple boat mounted in a baffled enclosure that could be placed in a conventional vacuum bell jar, obviating the need for a dedicated complete vacuum system. Substrates were 102 mm × 127 mm × 0.05 mm cleaved mica sheets, coated with 0.1 μm of NaCl, then with approximately 50 μg/cm 2 of cellulose nitrate. These were mounted on poly(methyl methacrylate) sheets 3 mm thick that were in turn clamped to a massive aluminum block for thermal stability. Details of the processes for evaporation, float off, and mounting are given, and the resulting foils described.

  5. Bombarding insulating foils with highly energetic ions

    NASA Astrophysics Data System (ADS)

    Lanzanò, G.; de Filippo, E.; Hagmann, S.; Rothard, H.; Volant, C.

    Insulating (MYLAR), semi-insulating (MYLAR-Au) and conducting foils have been bombarded by very energetic 64 MeV u-1 78Kr32+ ions. The velocity spectra of fast electrons emitted in the backward and forward directions have been measured and analyzed as a function of the elapsed time in the run. A shift of binary encounter and convoy electrons emitted in the forward direction toward lower velocities has been observed with insulating targets. No such shift occurs with metallic targets. The surface potential evolves with time (i.e. ion fluence) both at forward and backward emission angle. It is shown that strong bulk charging of insulating targets leads to a positive potential as high as 9 kV before charge breakdown.

  6. Preparation of selenium coatings onto beryllium foils

    SciTech Connect

    Erikson, E.D.; Tassano, P.L.; Reiss, R.H.; Griggs, G.E.

    1984-09-01

    A technique for preparing selenium films onto 50.8 microns thick beryllium foils is described. The selenium was deposited in vacuum from a resistance heated evaporation source. Profilometry measurements of the coatings indicate deposit thicknesses of 5.5, 12.9, 37.5, 49.8 and 74.5 microns. The control of deposition rate and of coating thickness was facilitated using a commercially available closed-loop programmable thin film controller. The x-ray transmission of the coated substrates was measured using a tritiated zirconium source. The transmissivities of the film/substrate combination are presented for the range of energies from 4 to 20 keV. 15 references, 3 figures.

  7. Foil Gas Thrust Bearings for High-Speed Turbomachinery

    NASA Technical Reports Server (NTRS)

    Edmonds, Brian; DellaCorte, Christopher; Dykas, Brian

    2010-01-01

    A methodology has been developed for the design and construction of simple foil thrust bearings intended for parametric performance testing and low marginal costs, supporting continued development of oil-free turbomachinery. A bearing backing plate is first machined and surface-ground to produce flat and parallel faces. Partial-arc slots needed to retain the foil components are then machined into the plate by wire electrical discharge machining. Slot thicknesses achievable by a single wire pass are appropriate to accommodate the practical range of foil thicknesses, leaving a small clearance in this hinged joint to permit limited motion. The backing plate is constructed from a nickel-based superalloy (Inconel 718) to allow heat treatment of the entire assembled bearing, as well as to permit hightemperature operation. However, other dimensionally stable materials, such as precipitation-hardened stainless steel, can also be used for this component depending on application. The top and bump foil blanks are cut from stacks of annealed Inconel X-750 foil by the same EDM process. The bump foil has several azimuthal slits separating it into five individual bump strips. This configuration allows for variable bump spacing, which helps to accommodate the effects of the varying surface velocity, thermal crowning, centrifugal dishing, and misalignment. Rectangular tabs on the foil blanks fit into the backing plate slots. For this application, a rather traditional set of conventionally machined dies is selected, and bump foil blanks are pressed into the dies for forming. This arrangement produces a set of bump foil dies for foil thrust bearings that provide for relatively inexpensive fabrication of various bump configurations, and employing methods and features from the public domain.

  8. High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness

    SciTech Connect

    Vivek, A. Hansen, S. R.; Daehn, Glenn S.

    2014-07-15

    Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-based analytical model was developed and found to have reasonable agreement with experiment.

  9. Producing Foils From Direct Cast Titanium Alloy Strip

    NASA Technical Reports Server (NTRS)

    Stuart, T. A.; Gaspar, T. A.; Sukonnik, I. M.; Semiatan, S. L.; Batawi, E.; Peters, J. A.; Fraser, H. L.

    1996-01-01

    This research was undertaken to demonstrate the feasibility of producing high-quality, thin-gage, titanium foil from direct cast titanium strip. Melt Overflow Rapid Solidification Technology (MORST) was used to cast several different titanium alloys into 500 microns thick strip, 10 cm wide and up to 3 m long. The strip was then either ground, hot pack rolled or cold rolled, as appropriate, into foil. Gamma titanium aluminide (TiAl) was cast and ground to approximately 100 microns thick foil and alpha-2 titanium aluminide (Ti3AI) was cast and hot pack rolled to approximately 70 microns thick foil. CP Ti, Ti6Al2Sn4Zr2Mo, and Ti22AI23Nb (Orthorhombic), were successfully cast and cold-rolled into good quality foil (less than 125 microns thick). The foils were generally fully dense with smooth surfaces, had fine, uniform microstructures, and demonstrated mechanical properties equivalent to conventionally produced titanium. By eliminating many manufacturing steps, this technology has the potential to produce thin gage, titanium foil with good engineering properties at significantly reduced cost relative to conventional ingot metallurgy processing.

  10. Pigmented foils for radiative cooling and condensation irrigation

    SciTech Connect

    Nilsson, T.M.J.; Vargas, W.E.; Niklasson, G.A.

    1994-12-31

    This paper reports on the development of pigmented polyethylene foils for radiative cooling. The optical properties of the foils were optimized for applications in day-time radiative cooling and water condensation. The authors first study highly scattering foils used as convection shields. These cover foils combine a high solar reflectance and a high transmittance in the atmospheric window region in the infrared. Different pigment materials were studied and ZnS was the only one that could prevent heating of an underlying blackbody at noon, with the sun in its zenith. A 400 {micro}m thick ZnS pigmented polyethylene foil with a pigment volume fraction of 0.15 was tested in Tanzania. At noon the observed temperature of the covered blackbody was only 1.5 K above the ambient. Secondly, they study the potential for condensation of water in an arid region. Pigmented foils for this purpose should combine a high solar reflectance and a high infrared emittance, in order to promote condensation by the radiative cooling effect. Titanium dioxide is a fairly good infrared emitter, but the emittance can be improved by using a mixture of TiO{sub 2} and BaSO{sub 4} pigments or only employing a composite SiO{sub 2}/TiO{sub 2}. Field tests with a 390 {micro}m thick polyethylene foil with TiO{sub 2} and BaSO{sub 4} pigments gave encouraging results.

  11. Compliant Foil Journal Bearing Performance at Alternate Pressures and Temperatures

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.; Puleo, Bernadette J.

    2008-01-01

    An experimental test program has been conducted to determine the highly loaded performance of current generation gas foil bearings at alternate pressures and temperatures. Typically foil bearing performance has been reported at temperatures relevant to turbomachinery applications but only at an ambient pressure of one atmosphere. This dearth of data at alternate pressures has motivated the current test program. Two facilities were used in the test program, the ambient pressure rig and the high pressure rig. The test program utilized a 35 mm diameter by 27 mm long foil journal bearing having an uncoated Inconel X-750 top foil running against a shaft with a PS304 coated journal. Load capacity tests were conducted at 3, 6, 9, 12, 15, 18, and 21 krpm at temperatures from 25 to 500 C and at pressures from 0.1 to 2.5 atmospheres. Results show an increase in load capacity with increased ambient pressure and a reduction in load capacity with increased ambient temperature. Below one-half atmosphere of ambient pressure a dramatic loss of load capacity is experienced. Additional lightly loaded foil bearing performance in nitrogen at 25 C and up to 48 atmospheres of ambient pressure has also been reported. In the lightly loaded region of operation the power loss increases for increasing pressure at a fixed load. Knowledge of foil bearing performance at operating conditions found within potential machine applications will reduce program development risk of future foil bearing supported turbomachines.

  12. An Assessment of Triton College Student Retention: Fall 1978--Spring 1979. Vol. XIV, Number 20.

    ERIC Educational Resources Information Center

    Bakshis, Robert

    A survey of two random samples of 500 students drawn from lists of returning and non-returning students at Triton College was conducted to study student retention between Fall 1978 and Spring 1979. Data, gathered from 248 returning and 159 non-returning respondents, were analyzed in terms of: (1) student educational intent, (2) reasons for…

  13. Photometric Monitoring of Triton at Sommers-Bausch Observatory in 2000

    NASA Technical Reports Server (NTRS)

    Young, L. A.; Bullock, M. A.; Colwell, W. B.; Durda, D. D.; Gleason, K.; Parker, J. W.; Stern, S. A.; Terrell, D.; Young, E. F.

    2001-01-01

    We undertook pilot program to develop an observing and analysis strategy that can be used to measure Triton's B and V albedos with 0.05 magnitude accuracy at moderate-to-small telescopes, under moderate-to-poor seeing conditions. Additional information is contained in the original extended abstract.

  14. Renewal for the Eighties: A Proposal for Maintaining Curricular Excellence at Triton College.

    ERIC Educational Resources Information Center

    Triton Coll., River Grove, IL.

    The results of a study conducted at Triton College to assess its curriculum in light of current educational research are presented in this report. The first section describes the structure and charge of the Curriculum Study Committee, as well as its activities, which included a month of individual study of several books and articles relating to…

  15. Role of triton X-100 and hydrothermal treatment on the morphological features of nanoporous hydroxyapatite nanorods.

    PubMed

    Iyyappan, E; Wilson, P; Sheela, K; Ramya, R

    2016-06-01

    Hydroxyapatite (HA) particles were synthesized using Ca(NO3)2·4H2O and (NH4)2HPO4 as precursors with varying contents of non-ionic surfactant viz., triton X-100 (organic modifier) via co-precipitation method followed by hydrothermal treatment. The prepared HA particles have been characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Energy Dispersive X-ray Analysis (EDX), High Resolution Scanning Electron Microscopy (HRSEM), High Resolution Transmission Electron Microscopy (HRTEM) and Nitrogen adsorption-desorption experiments. The XRD and FTIR studies indicate the formation of HA phase in all the synthesized samples. The specific roles of triton X-100 and hydrothermal treatment in dispersing and in directing the crystal growth respectively have been discussed by comparing the observations from individual experiments using triton X-100 and hydrothermal treatment with that of combined protocol involving both. The plausible mechanism for the individual roles of both triton X-100 and hydrothermal treatment have been proposed. PMID:27040250

  16. Application of Triton surfactant adsorption on Si surface for fabrication of 45° micromirrors

    NASA Astrophysics Data System (ADS)

    Rola, Krzysztof P.; Zubel, Irena

    2013-07-01

    Anisotropic etching process of Si (100) and (110) planes in low concentrated potassium hydroxide (KOH) solutions containing Triton X-100 surfactant is studied in this paper. Addition of a little amount of the surfactant to the etchant considerably reduces etch rates of both the planes, though the etch rate ratio R(100)/R(110) > 1 is obtained. The (110) surface roughness is significantly decreased when Triton is added to the solution, too. Therefore, the {110} sidewall planes could be used as micromirrors inclined at 45° towards the (100) substrate. The {110} surface roughness is low in a wide range of Triton concentration, which gives some flexibility in the choice of surfactant concentration for fabrication of smooth micromirrors. Better understanding of etching processes with surfactants could help select a composition of the etching solution which yields little rough {110} planes. For that reason, the adsorption of Triton molecules on Si surface is investigated using contact angle measurements. The results show that the (110) surface is more hydrophilic as well as better wetted by the surfactant solution than the (100) one, though both the planes are rather hydrophobic. This suggests that a little more hydrophilic surface should be more advantageous to the surfactant adsorption. The explanation, based on literature reports and theoretical considerations, is proposed and associated with the etching results.

  17. Mechanical properties of micro- and nanocrystalline diamond foils

    PubMed Central

    Lodes, M. A.; Kachold, F. S.; Rosiwal, S. M.

    2015-01-01

    Diamond coating of suitable template materials and subsequent delamination allows for the manufacturing of free-standing diamond foil. The evolution of the microstructure can be influenced by secondary nucleation via control of process conditions in the hot-filament chemical vapour deposition process. Bending tests show extraordinarily high strength (more than 8 GPa), especially for diamond foils with nanocrystalline structure. A detailed fractographic analysis is conducted in order to correlate measured strength values with crack-initiating defects. The size of the failure causing flaw can vary from tens of micrometres to tens of nanometres, depending on the diamond foil microstructure as well as the loading conditions. PMID:25713455

  18. Material compatibility evaluation for liquid oxygen turbopump fluid foil bearings

    NASA Technical Reports Server (NTRS)

    Stoltzfus, J. M.; Dees, J.; Gu, A.; Dolan, F.

    1992-01-01

    Three series of tests were carried out on three polymer-coated Inconel substrate materials, Teflon S, polyimide bonded graphite fluoride (PBGF), and Teflon, which are considered for use in fluid foil bearings for a liquid oxygen turbopump. All the candidate materials passed the liquid oxygen frictional heating test. During the gaseous oxygen frictional heating test, all coatings wore off before ignition occured. Both Teflon S and PBGF coated foils passed 100 start/stop cycles against chrome-plated Inconel 718 shaft in the direct foil bearing lift-off simulation test in liquid oxygen.

  19. Method for laser welding ultra-thin metal foils

    DOEpatents

    Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

    1996-03-26

    A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld. 5 figs.

  20. Method for laser welding ultra-thin metal foils

    DOEpatents

    Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

    1996-01-01

    A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld.

  1. Hermetic packaging of drugs: optimized sealing of foil pouches.

    PubMed

    Auslander, D E; Gilbert, S G

    1976-07-01

    Factors affecting the sealing of foil packages were studied in the sealing of foil packages were studied in three laboratories. The relationship of sealing temperature (with machine speed and pressure kept constant) to the incidence of defective packages was determined. The maximum acceptable limit for defective pouches was 1%. Three tests were employed to detect defects: vacuum-dye, seal strength, and pressurized ammonia vapor. Only the last was sensitive enough to determine the optimum sealing conditions. This test also was capable of detecting leakage sites. Replacement of the cellophane layer of the foil laminate with polyvinylidene chloride-coated polyester improved the barrier properties of the package. PMID:957113

  2. Mechanical properties of micro- and nanocrystalline diamond foils.

    PubMed

    Lodes, M A; Kachold, F S; Rosiwal, S M

    2015-03-28

    Diamond coating of suitable template materials and subsequent delamination allows for the manufacturing of free-standing diamond foil. The evolution of the microstructure can be influenced by secondary nucleation via control of process conditions in the hot-filament chemical vapour deposition process. Bending tests show extraordinarily high strength (more than 8 GPa), especially for diamond foils with nanocrystalline structure. A detailed fractographic analysis is conducted in order to correlate measured strength values with crack-initiating defects. The size of the failure causing flaw can vary from tens of micrometres to tens of nanometres, depending on the diamond foil microstructure as well as the loading conditions. PMID:25713455

  3. Method of fabricating a uranium-bearing foil

    SciTech Connect

    Gooch, Jackie G.; DeMint, Amy L.

    2012-04-24

    Methods of fabricating a uranium-bearing foil are described. The foil may be substantially pure uranium, or may be a uranium alloy such as a uranium-molybdenum alloy. The method typically includes a series of hot rolling operations on a cast plate material to form a thin sheet. These hot rolling operations are typically performed using a process where each pass reduces the thickness of the plate by a substantially constant percentage. The sheet is typically then annealed and then cooled. The process typically concludes with a series of cold rolling passes where each pass reduces the thickness of the plate by a substantially constant thickness amount to form the foil.

  4. On the performance of hybrid foil-magnetic bearings

    SciTech Connect

    Heshmat, H.; Chen, H.M.; Walton, J.F. II.

    2000-01-01

    Recent technological advancements make hybridization of the magnetic and foil bearing both possible and extremely attractive. Operation of the foil/magnetic bearings takes advantage of the strengths of each individual bearing while minimizing each others weaknesses. In this paper one possible hybrid foil and magnetic bearing arrangement is investigated and sample design and operating parameters are presented. One of the weaknesses of the foil bearings, like any hydrodynamic bearing, is that contact between the foil bearing and the shaft occurs at rest or at very low speeds and it has low load carrying capacity at low speed. For high speed applications, AMBs are, however, vulnerable to rotor-bending or structural resonances that can easily saturate power amplifiers and make the control system unstable. Since the foil bearing is advantageous for high speed operation with a higher load carrying capacity, and the magnetic bearing is so in low speed range, it is a natural evolution to combine them into a hybrid bearing system thus utilizing the advantages of both. To take full advantage of the foil and magnetic elements comprising a hybrid bearing, it is imperative that the static and dynamic characteristics of each bearing be understood. This paper describes the development of a new analysis technique that was used to evaluate the performance of a class of gas-lubricated journal bearing. Unlike conventional approaches, the solution of the governing hydrodynamic equations dealing with compressible fluid is coupled with the structural resiliency of the bearing surface. The distribution of the fluid film thickness and pressures, as well as the shear stresses in a finite-width journal bearing, are computed. Using the Finite Element (FE) method, the membrane effect of an elastic top foil was evaluated and included in the overall analytical procedure. Influence coefficients were generated to address the elasticity effects of combined top foil and elastic foundation on the

  5. Functional multi-band THz meta-foils

    PubMed Central

    Wu, Jianfeng; Moser, Herbert O.; Xu, Su; Jian, Linke; Banas, Agnieszka; Banas, Krzysztof; Chen, Hongsheng; Bettiol, Andrew A.; Breese, Mark B. H.

    2013-01-01

    In this paper, we present the first experimental demonstration of double- and triple-band negative refraction index meta-foils in the terahertz (THz) region. Multi-band meta-foils constructed by multi-cell S-string resonators in a single structure exhibit simultaneously negative permittivity and negative permeability responses at multiple frequencies. The phenomena are confirmed by numerical simulations and Fourier transform infrared spectroscopy measurements. The flexible, freestanding multi-band meta-foils provide a promising candidate for the development of multi-frequency THz materials and devices. PMID:24346309

  6. Elevated Temperature Tensile Tests on DU–10Mo Rolled Foils

    SciTech Connect

    Schulthess, Jason

    2014-09-01

    Tensile mechanical properties for uranium-10 wt.% molybdenum (U–10Mo) foils are required to support modeling and qualification of new monolithic fuel plate designs. It is expected that depleted uranium-10 wt% Mo (DU–10Mo) mechanical behavior is representative of the low enriched U–10Mo to be used in the actual fuel plates, therefore DU-10Mo was studied to simplify material processing, handling, and testing requirements. In this report, tensile testing of DU-10Mo fuel foils prepared using four different thermomechanical processing treatments were conducted to assess the impact of foil fabrication history on resultant tensile properties.

  7. Study on metal foil explosion using high current

    NASA Astrophysics Data System (ADS)

    Mihara, Takayuki; Matsuo, N.; Otsuka, M.; Itoh, S.

    2009-12-01

    In the high energy processing using explosive, there are variety of application examples which is explosion welding of differential metallic plate and powder compaction of diamond. However a rule legal to explosives is severe and needs many efforts for handling qualification acquisition, maintenance, and security. In this research, the metallic foil explosion using high current is paid my attention to the method to obtain linear or planate explosive initiation easily, and the main evaluation of metallic foil explosion was conducted. The explosion power was evaluated by observing optically the underwater shock wave generated from the metallic foil explosion.

  8. Study on metal foil explosion using high current

    NASA Astrophysics Data System (ADS)

    Mihara, Takayuki; Matsuo, N.; Otsuka, M.; Itoh, S.

    2010-03-01

    In the high energy processing using explosive, there are variety of application examples which is explosion welding of differential metallic plate and powder compaction of diamond. However a rule legal to explosives is severe and needs many efforts for handling qualification acquisition, maintenance, and security. In this research, the metallic foil explosion using high current is paid my attention to the method to obtain linear or planate explosive initiation easily, and the main evaluation of metallic foil explosion was conducted. The explosion power was evaluated by observing optically the underwater shock wave generated from the metallic foil explosion.

  9. Synchronization and Phase Dynamics of Oscillating Foils

    NASA Astrophysics Data System (ADS)

    Finkel, Cyndee L.

    In this work, a two-dimensional model representing the vortices that animals produce, when they are ying/swimming, was constructed. A D{shaped cylinder and an oscillating airfoil were used to mimic these body{shed and wing{generated vortices, respectively. The parameters chosen are based on the Reynolds numbers similar to that which is observed in nature (˜10 4). In order to imitate the motion of ying/swimming, the entire system was suspended into a water channel from frictionless air{bearings. The position of the apparatus in the channel was regulated with a linear, closed loop PI controller. Thrust/drag forces were measured with strain gauges and particle image velocimetry (PIV) was used to examine the wake structure that develops. The Strouhal number of the oscillating airfoil was compared to the values observed in nature as the system transitions between the accelerated and steady states. The results suggest that self-regulation restricts the values of the Strouhal number to a certain range where no other external sensory input is necessary. As suggested by previous work, this self-regulation is a result of a limit cycle process that stems from nonlinear periodic oscillations. The limit cycles were used to examine the synchronous conditions due to the coupling of the foil and wake vortices. Noise is a factor that can mask details of the synchronization. In order to control its effect, we study the locking conditions using an analytic technique that only considers the phases. Our results show that the phase locking indices are dependent on the Strouhal value as it converges to a frequency locking ratio of ≃0:5. This indicates that synchronization occurs during cruising between the motion of the foil and the measured thrust/drag response of the uid forces. The results suggest that Strouhal number selection in steady forward natural swimming and ying is the result of a limit cycle process and not actively controlled by an organism. An implication of this is

  10. Titan's photochemical model: Further update, oxygen species, and comparison with Triton and Pluto

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.

    2012-12-01

    My photochemical model for Titan's atmosphere and ionosphere is improved using the Troe approximation for termolecular reactions and inclusion of four radiative association reactions from those calculated by Vuitton et al. (2012). Proper fitting of eddy diffusion results in a reduction of the mean difference between 63 observed mixing ratios and their calculated values from a factor of 5 in my previous models for Titan to a factor of 3 in the current model. Oxygen chemistry on Titan is initiated by influxes of H2O from meteorites and O+ from magnetospheric interactions with the Saturn rings and Enceladus. Two versions of the model were calculated, with and without the O+ flux. Balances of CO, CO2, H2O, and H2CO are discussed in detail for both versions. The calculated model with the O+ flux agrees with the observations of CO, CO2, and H2O, including recent H2O CIRS limb observations and measurements by the Herschel Space Observatory. Major observational data and photochemical models for Triton and Pluto are briefly discussed. While the basic atmospheric species N2, CH4, and CO are similar on Triton and Pluto, properties of their atmospheres are very different with atomic species and ions dominating in Triton's upper atmosphere and ionosphere opposed to the molecular composition on Pluto. Calculations favor a transition between two types of photochemistry at the CH4 mixing ratio of ∼5×10-4. Therefore Triton's current photochemistry is still similar to that at the Voyager flyby despite the observed increase in N2 and CH4. The meteorite H2O results in precipitation of CO on Triton and CO2 on Pluto near perihelion.

  11. Characterization of Electrodeposited Technetium on Gold Foil

    SciTech Connect

    Mausolf, Edward; Poineau, Frederic; Hartmann, Thomas; Droessler, Janelle; Czerwinski, Ken

    2011-11-17

    The reduction and electrodeposition of TcO{sub 4}{sup -} on a smooth gold foil electrode with an exposed area of 0.25 cm{sup 2} was performed in 1 M H{sub 2}SO{sub 4} supporting electrolyte using bulk electrolysis with a constant current density of 1.0 A/cm{sup 2} at a potential of -2.0 V. Significant hydrogen evolution accompanied the formation of Tc deposits. Tc concentrations consisted of 0.01 M and 2 x 10{sup -3} M and were electrodeposited over various times. Deposited fractions of Tc were characterized by powder x-ray diffraction, x-ray absorption fine structure spectroscopy, and scanning electron microscopy with the capability to measure semiquantitative elemental compositions by energy-dispersive x-ray emission spectroscopy. Results indicate the presence of Tc metal on all samples as the primary electrodeposited constituent for all deposition times and Tc concentrations. Thin films of Tc have been observed followed by the formation of beads that are removable by scratching. After 2000, the quantity of Tc removed from solution and deposited was 0.64 mg Tc per cm{sup 2}. The solution, after electrodeposition, showed characteristic absorbances near 500 nm corresponding to hydrolyzed Tc(IV) produced during deposition of Tc metal. No detectable Tc(IV) was deposited to the cathode.

  12. Delivery of optical contrast agents using Triton-X100, part 1: reversible permeabilization of live cells for intracellular labeling

    NASA Astrophysics Data System (ADS)

    van de Ven, Anne L.; Adler-Storthz, Karen; Richards-Kortum, Rebecca

    2009-03-01

    Effective delivery of optical contrast agents into live cells remains a significant challenge. We sought to determine whether Triton-X100, a detergent commonly used for membrane isolation and protein purification, could be used to effectively and reversibly permeabilize live cells for delivery of targeted optical contrast agents. Although Triton-X100 is widely recognized as a good cell permeabilization agent, no systematic study has evaluated the efficiency, reproducibility, and reversibility of Triton-X100-mediated permeabilization in live mammalian cells. We report a series of studies to characterize macromolecule delivery in cells following Triton-X100 treatment. Using this approach, we demonstrate that molecules ranging from 1 to 150 kDa in molecular weight can be reproducibly delivered into live cells by controlling the moles of Triton-X100 relative to the number of cells to be treated. When Triton-X100 is administered at or near the minimum effective concentration, cell permeabilization is generally reversed within 24 h, and treated cells continue to proliferate and show metabolic activity during the restoration of membrane integrity. We conclude that Triton-X100 is a promising permeabilization agent for efficient and reproducible delivery of optical contrast agents into live mammalian cells.

  13. Indium foil with beryllia washer improves transistor heat dissipation

    NASA Technical Reports Server (NTRS)

    Hilliard, J.; John, J. E. A.

    1964-01-01

    Indium foil, used as an interface material in transistor mountings, greatly reduces the thermal resistance of beryllia washers. This method improves the heat dissipation of power transistors in a vacuum environment.

  14. Stratification in Al and Cu foils exploded in vacuum

    SciTech Connect

    Baksht, R. B.; Rousskikh, A. G.; Zhigalin, A. S.; Artyomov, A. P.; Oreshkin, V. I.

    2015-10-15

    An experiment with exploding foils was carried out at a current density of 0.7 × 10{sup 8} A/cm{sup 2} through the foil with a current density rise rate of about 10{sup 15} A/cm{sup 2} s. To record the strata arising during the foil explosions, a two-frame radiographic system was used that allowed tracing the dynamics of strata formation within one shot. The original striation wavelength was 20–26 μm. It was observed that as the energy deposition to a foil stopped, the striation wavelength increased at a rate of ∼(5–9) × 10{sup 3} cm/s. It is supposed that the most probable reason for the stratification is the thermal instability that develops due to an increase in the resistivity of the metal with temperature.

  15. Positron annihilation lifetime spectroscopy study of Kapton thin foils

    NASA Astrophysics Data System (ADS)

    Kanda, G. S.; Ravelli, L.; Löwe, B.; Egger, W.; Keeble, D. J.

    2016-01-01

    Variable energy positron annihilation lifetime spectroscopy (VE-PALS) experiments on polyimide material Kapton are reported. Thin Kapton foils are widely used in a variety of mechanical, electronic applications. PALS provides a sensitive probe of vacancy-related defects in a wide range of materials, including open volume in polymers. Varying the positron implantation energy enables direct measurement of thin foils. Thin Kapton foils are also commonly used to enclose the positron source material in conventional PALS measurements performed with unmoderated radionuclide sources. The results of depth-profiled positron lifetime measurements on 7.6 μm and 25 μm Kapton foils are reported and determine a dominant 385(1) ps lifetime component. The absence of significant nanosecond lifetime component due to positronium formation is confirmed.

  16. The transonic multi-foil Augmentor-Wing

    NASA Technical Reports Server (NTRS)

    Farbridge, J. E.; Smith, R. C.

    1977-01-01

    The paper describes the development of a transonic blown multi-foil Augmentor-Wing airfoil section that has a thickness/chord (t/c) value of 0.18. In comparison with an unblown single-foil supercritical section of the same overall t/c the new multi-foil section is characterized by an increased drag rise Mach number, increased buffet boundaries, and a reduction in 'effective' drag due to blowing. Potential advantages of the Augmentor-Wing are considered and the testing of three high-speed models in a trisonic pressurized wind tunnel (possessing a two-dimensional transonic insert) is discussed. The data indicate that a very thick wing is feasible since separations toward the rear of the main foil can be controlled both by shroud location and augmentor blowing.

  17. Coherent multiple-foil x-ray transition radiation

    SciTech Connect

    Moran, M.J.; Chang, B.; Schneider, M.B.

    1993-08-25

    Intense x-ray transition radiation can be generated when relativistic electrons pass through a multiple-foil target. When the foil spacing is periodic, the transition radiation can be spatially coherent with respect to the target period. The spatial coherence can be evident in the spectra and angular distributions of transition radiation from such targets. A series of experiments has measured coherent transition radiation distributions from multiple-foil targets (up to six foils) with spacings of 50 {mu}m and 100 {mu}m. The electron energy was about 75 MeV and the photon energies were about 200 eV. Agreement between calculation and experimental data is excellent.

  18. Stratification in Al and Cu foils exploded in vacuum

    NASA Astrophysics Data System (ADS)

    Baksht, R. B.; Rousskikh, A. G.; Zhigalin, A. S.; Oreshkin, V. I.; Artyomov, A. P.

    2015-10-01

    An experiment with exploding foils was carried out at a current density of 0.7 × 108 A/cm2 through the foil with a current density rise rate of about 1015 A/cm2 s. To record the strata arising during the foil explosions, a two-frame radiographic system was used that allowed tracing the dynamics of strata formation within one shot. The original striation wavelength was 20-26 μm. It was observed that as the energy deposition to a foil stopped, the striation wavelength increased at a rate of ˜(5-9) × 103 cm/s. It is supposed that the most probable reason for the stratification is the thermal instability that develops due to an increase in the resistivity of the metal with temperature.

  19. Evidence of muonium formation using thin gold foils in vacuum

    NASA Technical Reports Server (NTRS)

    Barnett, B. A.; Chang, C. Y.; Steinberg, P.; Yodh, G. B.; Orr, H. D.; Carroll, J. B.; Eckhause, M.; Kane, J. R.; Spence, C. B.; Hsieh, C. S.

    1977-01-01

    The production of thermal muonium in a vacuum region has been investigated using an array of 200 thin (about 1000 A thick) gold foils exposed to a stopping positive-muon beam. By examining the observed time dependence of the positive-muon decay spectra in various transverse magnetic field, it is estimated that the lower limit of the probability of muonium formation by these gold foils placed in vacuum was 0.28 plus or minus 0.05.

  20. Two-Dimensional Dynamic Simulation of a Continuous Foil Bearing

    NASA Technical Reports Server (NTRS)

    Braun, M. Jack; Choy, F. K.; Dzodzo, Milorad; Hsu, J.

    1996-01-01

    In this paper, the two dimensional(radial and circumferential) transient Navier-Stokes equations are used to solve the hydrodynamic problem in conjunction with the time dependent motion of the journal, and the deformable, spring supported foil. The elastic deformation of the foil and its supports are simulated by a finite element model. The time-dependent Navier-Stokes formulation is used to solve for the interaction between the fluid lubricant, the motion of the journal and the deformable foil boundary. The steady state, the quasi-transient and the full transient dynamic simulation of the foil-fluid journal interaction are examined on a comparative basis. For the steady state simulation, the fluid lubricant pressures are evaluated for a particular journal position, by means of an iterative scheme until convergence is achieved in both the fluid pressures and the corresponding foil deformation. For the quasi-transient case, the transient motion of the journal is calculated using a numerical integration scheme for the velocity and displacement of the journal. The deformation of the foil is evaluated through numerical iteration in feedback mode with the fluid film pressure generated by the journal motion until convergence at every time step is achieved. For the full transient simulation, a parallel real-time integration scheme is used to evaluate simultaneously the new journal position and the new deformed shape of the foil at each time step. The pressure of the fluid lubricant is iterated jointly with the corresponding journal position and the deformed foil geometry until convergence is achieved. A variable time-stepping Newmark-Beta integration procedure is used to evaluate the transient dynamics at each time step of the bearing.

  1. Carbon-Fiber/Epoxy Tube Lined With Aluminum Foil

    NASA Technical Reports Server (NTRS)

    Gernet, Nelson J.; Kerr, Gregory K.

    1995-01-01

    Carbon-fiber/epoxy composite tube lined with welded aluminum foil useful as part of lightweight heat pipe in which working fluid ammonia. Aluminum liner provides impermeability for vacuum seal, to contain ammonia in heat pipe, and to prevent flow of noncondensable gases into heat pipe. Similar composite-material tubes lined with foils also incorporated into radiators, single- and two-phase thermal buses, tanks for storage of cryogenic materials, and other plumbing required to be lightweight.

  2. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Tin-coated lead foil capsules for wine bottles... lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one... covering applied over the cork and neck areas) on wine bottles to prevent insect infestation, as a...

  3. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Tin-coated lead foil capsules for wine bottles. 189... lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one... covering applied over the cork and neck areas) on wine bottles to prevent insect infestation, as a...

  4. On the lack of a magnetic signature of Triton's magnetospheric interaction on the Voyager 2 flyby trajectory

    NASA Technical Reports Server (NTRS)

    Neubauer, F. M.; Luettgen, Andrea; Ness, N. F.

    1991-01-01

    There is strong, albeit indirect, evidence for a sub-Alfvenic and transonic interaction between Triton and the Neptunian magnetosphere. A new inspection of magnetic field data around Triton encounter shows no evidence for the interaction. It is shown that this is due to the geometry of Triton's Alfvenic wings, which were probably too far from the spacecraft during the encounter. The situation is complicated by finite ion gyroradius effects, which tend to smear out the simple Alfven wings such as encountered at Io.

  5. Investigating the micellization of the triton-X surfactants: A non-invasive fluorometric and calorimetric approach

    NASA Astrophysics Data System (ADS)

    Jaiswal, Sunidhi; Mondal, Ramakanta; Paul, Deena; Mukherjee, Saptarshi

    2016-02-01

    Using intrinsic and extrinsic fluorescence approaches, we have studied the Critical Micelle Concentration (CMC) of three non-ionic surfactants namely, Triton X-114 (TX-114), Triton X-100 (TX-100) and Triton X-165 (TX-165) which differ in number of polyethylene oxide (PEO) groups. We have established that for TX-114 and TX-100, the external fluorophores C-153 and ANS support our intrinsic approach, whereas, for TX-165, the same is perhaps not true. This has been attributed to the different numbers of PEO groups constituting the surfactant systems. We have also studied the CMC using Isothermal Titration Calorimetry (ITC) which is in excellent harmony with our intrinsic approach.

  6. Electrospray ionization with aluminum foil: A versatile mass spectrometric technique.

    PubMed

    Hu, Bin; So, Pui-Kin; Yao, Zhong-Ping

    2014-03-19

    In this study, we developed a novel electrospray ionization (ESI) technique based on household aluminum foil (Al foil) and demonstated the desirable features and applications of this technique. Al foil can be readily cut and folded into desired configuration for effective ionization and for holding sample solution in bulk to allowing acquisition of durable ion signals. The present technique was demonstrated to be applicable in analysis of a wide variety of samples, ranging from pure chemical and biological compounds, e.g., organic compounds and proteins, to complex samples in liquid, semi-solid, and solid states, e.g., beverages, skincare cream, and herbal medicines. The inert, hydrophobic and impermeable surface of Al foil allows convenient and effective on-target extraction of solid samples and on-target sample clean-up, i.e., removal of salts and detergents from proteins and peptides, extending ESI device from usually only for sample loading and ionization to including sample processing. Moreover, Al foil is an excellent heat-conductor and highly heat-tolerant, permitting direct monitoring of thermal reactions, e.g., thermal denaturation of proteins. Overall, the present study showed that Al-foil ESI could be an economical and versatile method that allows a wide range of applications. PMID:24594810

  7. Induction Bonding of Prepreg Tape and Titanium Foil

    NASA Technical Reports Server (NTRS)

    Messier, Bernadette C.; Hinkley, Jeffrey A.; Johnston, Norman J.

    1998-01-01

    Hybrid structural laminates made of titanium foil and carbon fiber reinforced polymer composite offer a potential for improved performance in aircraft structural applications. To obtain information needed for the automated fabrication of hybrid laminates, a series of bench scale tests were conducted of the magnetic induction bonding of titanium foil and thermoplastic prepreg tape. Foil and prepreg specimens were placed in the gap of a toroid magnet mounted in a bench press. Several magnet power supplies were used to study power at levels from 0.5 to 1.75 kW and frequencies from 50 to 120 kHz. Sol-gel surface-treated titanium foil, 0.0125 cm thick, and PIXA/IM7 prepreg tape were used in several lay-up configurations. Data were obtained on wedge peel bond strength, heating rate, and temperature ramp over a range of magnet power levels and frequencies at different "power-on" times for several magnet gap dimensions. These data will be utilized in assessing the potential for automated processing. Peel strengths of foil-tape bonds depended on the maximum temperature reached during heating and on the applied pressure. Maximum peel strengths were achieved at 1.25kW and 8OkHz. Induction heating of the foil appears to be capable of good bonding up to 10 plies of tape. Heat transfer calculations indicate that a 20-40 C temperature difference exists across the tape thickness during heat-up.

  8. Instability studies in radial foil configurations on the COBRA generator

    NASA Astrophysics Data System (ADS)

    Gourdain, P.-A.; Greenly, J. B.; Hammer, D. A.; Knapp, P. F.; Kusse, B. R.; Pikuz, S. A.; Schrafel, P. C.; Shelkovenko, T. C.

    2010-11-01

    Radial foil configurations prove to be a very simple experimental set up to study high energy density plasmas. A 5-micron thin metallic foil lies flat over a stretcher which is connected to the anode of a pulsed power generator such as COBRA (1MA, 100 ns current rise time). The cathode contacts the foil at its geometrical center using a hollow stainless steel pin. As the foil ablates, JxB forces lift the foil leading to the formation a plasma bubble surrounding a central plasma column, which is a z-pinch. Force densities on this column should increase considerably as the initial pin diameter is diminished and we expect plasma properties to change accordingly. Based only on pin diameter considerations, radial foil explosions could produce magnetic pressures ranging from 160 kbar (for 2-mm pins) to 2.5 Mbar (for 0.5-mm pins). However, as the cathode diameter diminishes, instabilities appear earlier in the discharge, preventing the z-pinch implosion to occur at maximum current, de facto limiting plasma parameters. We investigate the cause of these instabilities, the possible means to reduce plasma instabilities and to improve plasma performances.

  9. Propulsion of a flexible foil in a fluid

    NASA Astrophysics Data System (ADS)

    Venkatraman, Kartik; Chaithanya, Ravi

    2008-11-01

    The dynamic properties such as time dependent pressure loading, free stream velocity, and local acceleration of the hydrofoil determine the instantaneous deformation of a flexible foil. The present work is concerned with the effect of structural dynamic terms and inertia loads on a flexible foil undergoing large amplitude rigid body harmonic wave-like motion in an unsteady potential flow. The hydrofoil structural dynamics is modeled as an Euler-Bernoulli beam finite element. The unsteady fluid dynamic force is evaluated using a numerical discrete vortex implementation of an unsteady incompressible potential flow model. The hydrofoil is fixed at its leading edge and it moves with velocity parallel to its length in the undeformed state. The propulsion of the hydro-elastic system is studied in terms of the mass ratio of the foil and the fluid, as well as its structural flexibility. It is shown that the thrust coefficient and propulsive efficiency of the flexible foil decreases with increase in structural flexibility. We made a comparison of the effect of structural flexibility on the thrust coefficient and propulsive efficiency considering models of the oscillating foil with inertia and without inertia effects present. Detailed parametric studies of the effect of different parameters on propulsion of the foil were made. Including inertia loads and structural dynamic terms significantly affect the propulsive efficiency and thrust coefficient.

  10. Globally shed wakes for three distinct retracting foil geometries

    NASA Astrophysics Data System (ADS)

    Steele, Stephanie; Triantafyllou, Michael

    2015-11-01

    In quickly retracting foils at an angle of attack, the boundary layer vorticity along with the added mass energy is immediately and globally shed from the body into the surrounding fluid. The deposited vorticity quickly reforms into lasting vortex structures, which could be used for purposes such as manipulating or exploiting the produced flow structures by additional bodies in the fluid. The globally shed wake thus entrains the added mass energy provided by the initially moving body, reflected by the value of the circulation left in the wake. In studying experimentally as well as numerically this phenomenon, we find that the three different tested geometries leave behind distinct wakes. Retracting a square-ended foil is undesirable because the deposited wake is complicated by three-dimensional ring vorticity effects. Retracting a tapered, streamlined-tipped foil is also undesirable because the shape-changing aspect of the foil geometry actually induces energy recovery back to the retracting foil, leaving a less energetic globally shed wake. Finally, a retracting hollow foil geometry avoids both of these detrimental effects, leaving relatively simple, yet energetic, vortex structures in the wake.

  11. FeN foils by nitrogen ion-implantation

    SciTech Connect

    Jiang, Yanfeng; Wang, Jian-Ping; Al Mehedi, Md; Fu, Engang; Wang, Yongqiang

    2014-05-07

    Iron nitride samples in foil shape (free standing, 500 nm in thickness) were prepared by a nitrogen ion-implantation method. To facilitate phase transformation, the samples were bonded on the substrate followed by a post-annealing step. By using two different substrates, single crystal Si and GaAs, structural and magnetic properties of iron nitride foil samples prepared with different nitrogen ion fluences were characterized. α″-Fe{sub 16}N{sub 2} phase in iron nitride foil samples was obtained and confirmed by the proposed approach. A hard magnetic property with coercivity up to 780 Oe was achieved for the FeN foil samples bonded on Si substrate. The feasibility of using nitrogen ion implantation techniques to prepare FeN foil samples up to 500 nm thickness with a stable martensitic phase under high ion fluences has been demonstrated. A possible mechanism was proposed to explain this result. This proposed method could potentially be an alternative route to prepare rare-earth-free FeN bulk magnets by stacking and pressing multiple free-standing thick α″-Fe{sub 16}N{sub 2} foils together.

  12. Infrared spectroscopy of Triton and Pluto ice analogs: the case for saturated hydrocarbons.

    PubMed

    Bohn, R B; Sandford, S A; Allamandola, L J; Cruikshank, D P

    1994-09-01

    The infrared transmission spectra and photochemical behavior of various organic compounds isolated in solid N2 ices, appropriate for applications to Triton and Pluto, are presented. It is shown that excess absorption in the surface spectra of Triton and Pluto, i.e., absorption not explained by present models incorporating molecules already identified on these bodies (N2, CH4, CO, and CO2), that starts near 4450 cm-1 (2.25 micrometers) and extends to lower frequencies, may be due to alkanes (C(n)H2n+2) and related molecules frozen in the nitrogen. Branched and linear alkanes may be responsible. Experiments in which the photochemistry of N2:CH4 and N(2):CH4:CO ices was explored demonstrate that the surface ices of Triton and Pluto may contain a wide variety of additional species containing H, C, O, and N. Of these, the reactive molecule diazomethane, CH2N2, is particularly important since it may be largely responsible for the synthesis of larger alkanes from CH4 and other small alkanes. Diazomethane would also be expected to drive chemical reactions involving organics in the surface ices of Triton and Pluto toward saturation, i.e., to reduce multiple CC bonds. The positions and intrinsic strengths (A values) of many of the infrared absorption bands of N2 matrix-isolated molecules of relevance to Triton and Pluto have also been determined. These can be used to aid in their search and to place constraints on their abundances. For example, using these A values the abundance ratios CH4/N2 approximately 1.3 x 10(-3), C2H4/N2 < or = 9.5 x 10(-7) and H2CO/N2 < or = 7.8 x 10(-7) are deduced for Triton and CH4/N2 approximately 3.1 x 10(-3), C2H4/N2 < or = 4.1 x 10(-6), and H2CO/N2 < or = 5.2 x 10(-6) deduced for Pluto. The small amounts of C2H4 and H2CO in the surface ices of these bodies are in disagreement with the large abundances expected from many theoretical models. PMID:11539177

  13. The Thermal Structure of Triton's Atmosphere: Results from the 1993 and 1995 Occultations

    NASA Astrophysics Data System (ADS)

    Olkin, C. B.; Elliot, J. L.; Hammel, H. B.; Cooray, A. R.; McDonald, S. W.; Foust, J. A.; Bosh, A. S.; Buie, M. W.; Millis, R. L.; Wasserman, L. H.; Dunham, E. W.; Young, L. A.; Howell, R. R.; Hubbard, W. B.; Hill, R.; Marcialis, R. L.; McDonald, J. S.; Rank, D. M.; Holbrook, J. C.; Reitsema, H. J.

    1997-09-01

    This paper presents new results about Triton's atmospheric structure from the analysis of all ground-based stellar occultation data recorded to date, including one single-chord occultation recorded on 1993 July 10 and nine occultation lightcurves from the double-star event on 1995 August 14. These stellar occultation observations made both in the visible and in the infrared have good spatial coverage of Triton, including the first Triton central-flash observations, and are the first data to probe the altitude level 20-100 km on Triton. The small-planet lightcurve model of J. L. Elliot and L. A. Young (1992,Astron. J.103,991-1015) was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude, indicating that Triton's atmosphere is spherically symmetric at ∼50-km altitude to within the error of the measurements; however, asymmetry observed in the central flash indicates the atmosphere is not homogeneous at the lowest levels probed (∼20-km altitude). From the average of the 1995 occultation data, the equivalent-isothermal temperature of the atmosphere is 47 ± 1 K and the atmospheric pressure at 1400-km radius (∼50-km altitude) is 1.4 ± 0.1 μbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989 (D. F. Strobel, X. Zhu, M. E. Summers, and M. H. Stevens, 1996,Icarus120,266-289). The atmospheric temperature from the occultation is 5 K colder than that predicted by the model and the observed pressure is a factor of 1.8 greater than the model. In our opinion, the disagreement in temperature and pressure is probably due to modeling problems at the microbar level, since measurements at this level have not previously been made. Alternatively, the difference could be due to seasonal change in Triton's atmospheric structure.

  14. SU-E-T-151: Enhanced Radiation Attenuation with Multi-Layer Foils

    SciTech Connect

    Warmington, L; Watanabe, Y

    2014-06-01

    Purpose: To evaluate the effect of increasing the number of thin high Z foils on the dose enhancement and the overall radiation attenuation with a 24MV photon beam. Methods: DOSXYZnrc was used to perform Monte Carlo simulations of multi-layer lead foil configurations. The foil size was 7cm x 7cm. and the foil thickness was adjusted to give a combined thickness of 1mm. The number of foils used was 4, 6, 8, and 10. The separation between foils was also varied from 3 to 9 mm. The Mohan 24MV energy spectrum was used as a photon source. The field size was 5cm x 5cm and SSD was 100 cm. The phantom size was 16cm × 16cm × 28cm. The number of histories ranged from 1 to 2 billion. The percentage difference of the dose between the medium with foils and the homogeneous water was computed along the beam axis. The minimum dose enhancement and the change of integrated dose between the foils were determined. Results: Increasing the number of foils resulted in a decrease in the minimum dose enhancement. The highest dose region occurred in the last section for the 4 and 6 foil cases, whereas the 8 and 10 foil configurations showed the maximum dose region towards the center of the foil group. Increasing the number of foils increased the total integrated dose between foils. For example, the total integrated dose increase between the first and the last foils with a 3mm foil separation were 34.2, 43.4, 57.4, and 64.7% for 4, 6, 8 and 10 foils, respectively. Conclusion: This work showed the degree of dose enhancement around multiple thin lead foils. The results suggest that the total attenuation of photon beam can be increased by increasing the number of foils with a fixed total foil thickness.

  15. Performance of Simple Gas Foil Thrust Bearings in Air

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2012-01-01

    Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In

  16. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terry; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Wood, Gary; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM (electric discharge machining). During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90% random fiber currently used in small 100 W Stirling space-power convertors in the Reynolds Number range of interest (50-100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6-9%; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to

  17. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM. During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90 percent random fiber currently used in small approx.100 W Stirling space-power convertors-in the Reynolds Number range of interest (50 to 100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6 to 9 percent; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to 1200 C

  18. High-Fidelity Lattice Physics Capabilities of the SCALE Code System Using TRITON

    SciTech Connect

    DeHart, Mark D

    2007-01-01

    Increasing complexity in reactor designs suggests a need to reexamine of methods applied in spent-fuel characterization. The ability to accurately predict the nuclide composition of depleted reactor fuel is important in a wide variety of applications. These applications include, but are not limited to, the design, licensing, and operation of commercial/research reactors and spent-fuel transport/storage systems. New complex design projects such as space reactors and Generation IV power reactors also require calculational methods that provide accurate prediction of the isotopic inventory. New high-fidelity physics methods will be required to better understand the physics associated with both evolutionary and revolutionary reactor concepts as they depart from traditional and well-understood light-water reactor designs. The TRITON sequence of the SCALE code system provides a powerful, robust, and rigorous approach for reactor physics analysis. This paper provides a detailed description of TRITON in terms of its key components used in reactor calculations.

  19. Triton's atmosphere - A source of N and H for Neptune's magnetosphere

    NASA Technical Reports Server (NTRS)

    Summers, Michael E.; Strobel, Darrell F.

    1991-01-01

    Mass loading of the Neptunian magnetosphere occurs primarily by thermal escape of H, H2, and N from Triton's upper atmosphere. The global escape rate of hydrogen is about 7 x 10 exp 25/s, determined by the global average methane photolysis rate, whereas the escape rate of nitrogen for the present preferred model is about 3.4 x 10 exp 25/s, and is controlled by the global and orbital average energy deposition rate due to precipitating magnetospheric electrons. The escape rate of H(+) and N(+) is less than 4 percent of the neutral escape rate and implies that mass loading of the Neptunian magnetosphere is not localized to Triton's corona. The ratio of hydrogen to nitrogen escape rates for the present preferred model is about 2:1, comparable to the H(+)/N(+) abundance ratio inferred for Neptune's magnetosphere.

  20. Narrow-band spectrophotometry of Ariel, Umbriel, Titania, Oberon, and Triton

    NASA Technical Reports Server (NTRS)

    Johnson, P. E.; Greene, T. F.; Shorthill, R. W.

    1978-01-01

    The spectral reflectances of Ariel, Umbriel, Titania, Oberon, and Triton were measured in 28 bandpasses between lambda 326 and lambda 976 nm on the night of 28/29 June 1974. These observations were made with the 200-in. Hale telescope and multichannel spectrometer. Bandpasses of 8 nm from lambda 326 to lambda 566 nm and 16 nm from lambda 592 to lambda 976 nm were employed. The spectral reflectances of Ariel, Oberon, and Titania increase from lambda 342 to lambda 534 nm and are relatively flat from lambda 550 to lambda 976 nm. Umbriel's reflectance decreases monotonically with increasing wavelength through the entire range of measured wavelengths. Triton is found to have a constant spectral reflectance.

  1. Fractal morphology of Beta vulgaris L. cell suspension culture permeabilized with Triton X-100®

    NASA Astrophysics Data System (ADS)

    Arenas-Ocampo, M.; Alamilla-Beltrán, L.; Vanegas-Espinoza, P. E.; Camacho-Díaz, B. H.; Campos-Mendiola, R.; Gutiérrez-López, G.; Jiménez-Aparicio, A.

    2012-02-01

    In this work, morphology of Beta vulgaris L. cells permeabilized with 0.7mM of Triton X-100® was evaluated using digital image processing and concepts of fractal dimension (perimeter- area relations). Important morphometric changes were found when the contact-time with chemical agent was increased. The size of cells decreased, the cells lost the roundness and their shape was more sinuous; this behaviour was a result of a probable shrinkage caused by the excess of exposure with the permeabilization agent. Morphology of B. vulgaris cells after permeabilization, exhibited a fractal nature since the slope of the ratio of the logarithm of the perimeter vs logarithm of the area was higher than unit. Fractal geometry of the cell morphology was affected as a result of the exposure to Triton X-100®. Those changes can be attributed to the loss of turgor and structure of the cell wall.

  2. Malignant triton tumor of the chest wall invading the lung. A case report and literature review

    PubMed Central

    Kamperis, E; Barbetakis, N; Asteriou, C; Kleontas, A; Christoforidou, V

    2013-01-01

    Background: Malignant triton tumor (MTT) is an histological deviation of malignant peripheral nerve sheath tumor with additional rhabdomyosarcomatous elements. It is very rare, profoundly aggressive, with a tendency to recur locally and metastasize early. If manifests itself more often in individuals with neurofibromatosis type I (NF-1) disease but also sporadically or post radiotherapy. Description of case: A 57-year-old male was admitted with a history of malignant triton tumor of the chest wall. Despite prior aggressive locoregional treatment including wide excision and adjuvant consolidating radiotherapy, the tumor recurred. The patient underwent a new operation and systemic chemotherapy, but expired a few months later due to disease progression. Conclusion: MTT is exceedingly malignant requiring multimodality treatment. The cornerstone of management is radical surgical resection with clear margins. Nevertheless, the overall prognosis remains dismal. PMID:24470743

  3. Molecular conformations of triton X 114 in the presence of a small amount of water

    NASA Astrophysics Data System (ADS)

    Zheliaskova, A.; Blinc, R.; Zupancic, I.; Sepe, A.; Derzhanski, A.

    1989-04-01

    The viscosity of the binary system Triton X 114-water and the self-diffusion of the detergent molecules of Triton X 114 have been determined experimentally in the region of small water concentrations (0-10 wt% of water). The temperature was varied from 10 to 50°C in steps of 5°C. The self-diffusion was measured by means of the NMR method. The viscosity of the samples was determined by an efflux viscosimeter. A deviation of the experimentally obtained temperature trend of the viscosity and of the molecular mobility from the theoretical expected exponential dependence was found. This may be due to the building of dimers from the detergent molecules, whose number increases in the low temperature interval.

  4. Anomalous Interaction of the Acetylcholine Receptor Protein with the Nonionic Detergent Triton X-114

    NASA Astrophysics Data System (ADS)

    Maher, Pamela A.; Singer, S. J.

    1985-02-01

    Integral membrane proteins that form water-filled channels through membranes often exist as aggregates of similar or identical subunits spanning the membrane. It has been suggested that the insertion into the membrane of the channel-forming domains of the subunits may impart unusual structural features to the membrane-intercalated portions of the protein. To test this proposal, we have investigated the interaction of a multisubunit channel-forming integral membrane protein, the acetylcholine receptor protein, with the nonionic detergent Triton X-114. Whereas non-channel-forming integral membrane proteins that have heretofore been studied from mixed micelles with the detergent, the acetylcholine receptor was excluded from the Triton X-114 micelles. The structural implications of this result are discussed.

  5. Present state and chemical evolution of the atmospheres of Titan, Triton, and Pluto

    NASA Technical Reports Server (NTRS)

    Lunine, J. I.; Atreya, S. K.; Pollack, J. B.

    1989-01-01

    An evaluation is made of the current understanding of the atmospheres of Titan, Triton, and Pluto, as well as of theoretical models for their origin and evolution. All three atmospheres contain methane, while Titan, and probably Triton, have nitrogen. The primary driver in the evolution of the Titan atmosphere has been the irreversible photolysis of methane. If a surface reservoir of liquid methane exists to resupply the atmosphere, it is subject to enrichment in ethane due to the long-term photolysis of methane. The key issue in the origin and early evolution of Titan's atmosphere is the source of molecular nitrogen; two schemes for the conversion of ammonia to nitrogen have been considered.

  6. Instabilities in foil implosions and the effect of radiation output

    SciTech Connect

    Oona, H.; Peterson, D.L.; Goforth, J.H.

    1995-08-01

    One of the aims of the Athena program at the Los Alamos National Laboratory is the generation of a high fluence of soft x-rays from the thermalization of an radially imploding foil. In the experiments in Athena program, a large axial current is passed through a cylindrical aluminum foil. Under the action of the Lorentz force, the resulting plasma accelerates toward the axis, thermalizes, and produces a fast soft x-ray pulse with a blackbody temperature up to several hundred electron volts. In order that there be the maximum power compression and the highest x-ray fluence and temperature, the plasma stagnation on axis must occur very promptly. This requires that the imploding plasma be as thin and symmetric as possible. A serious problem in the thermalization process is the formation of instabilities in the plasma due to the self-magnetic field that governs the implosion of foil. A large diagnostic effort was developed to capture the details of the implosion and instability growth in several foil implosion experiments. In this report, we will present visible light images and x-ray data designed to study the effects of foil mass, current, and initial perturbations on the instability growth during foil implosion. Representative data is presented from several experiments using the Pegasus capacitor bank system and the explosively driven Procyon system. These experiments are labeled Peg 25 and Peg 33 for the Pegasus experiments and PDD1, PDD2 and PRF0 for the Procyon experiments. In these experiments, all foils had radii of 5 centimeters but varied in mass and initial conditions. Experimental data from several shots were compared with each other and to a radiation magnetohydrodynamic (RMHD) computation and described in a separate paper.

  7. Composition and evolution of Triton's icy surface between 2002-2014 from SpeX/IRTF

    NASA Astrophysics Data System (ADS)

    Holler, Bryan J.; Young, Leslie A.; Grundy, William M.; Olkin, Cathy B.

    2015-11-01

    We observed Triton in the near-infrared (0.7-2.5 μm) over 63 nights using the SpeX instrument at NASA's Infrared Telescope Facility (IRTF) between 2002 and 2014. Triton’s spectrum has absorption features due to N2, CO, CH4, CO2, and H2O in this wavelength range. We calculated the equivalent width (or fractional band depth for H2O) of select absorption bands in each of the 63 night-averaged spectra. Longitudinal distributions for the volatile ices (N2, CO, CH4) show large rotational amplitude, while the non-volatile ices (CO2, H2O) show little amplitude over one Triton rotation. Absorption from N2 and CH4 increased over the period of the observations, whereas absorption from the non-volatile ices remained constant. The sub-solar latitude on Triton is currently at -42 degrees south, so some areas of Triton are visible for a full rotation. Combined with our findings, this suggests that the southern latitudes are dominated by non-volatile ices, with larger concentrations of volatile ices found in the observable region north of the equator. Changing viewing geometry over the period of the observations explains the increase in volatile absorption: As the sub-solar point moves northwards, more of the volatile-rich northern regions are coming directly into view. Geological evidence from Voyager 2 pointed to a southern hemisphere dominated by volatile ices; significant changes have occurred over the intervening quarter century.

  8. Deuteron and triton magnetic moments from NMR spectra of the hydrogen molecule

    NASA Astrophysics Data System (ADS)

    Puchalski, Mariusz; Komasa, Jacek; Pachucki, Krzysztof

    2015-08-01

    We present a theory and calculations of the nuclear magnetic shielding with finite nuclear mass effects and determine the magnetic moments of deuteron and triton using the known NMR spectra of HD and HT molecules. The results μd=0.857 438 234 6 (53 ) μN and μt=2.978 962 471 (10 ) μN are more accurate and in good agreement with the currently accepted values.

  9. Effects of sawtooth crashes on beam ions and fusion product tritons in JET

    NASA Astrophysics Data System (ADS)

    Marcus, F. B.; Adams, J. M.; Bond, D. S.; Hone, M. A.; Howarth, P. J. A.; Jarvis, O. N.; Loughlin, M. J.; Sadler, G. J.; Van Belle, P.; Watkins, N.

    1994-05-01

    The JET neutron emission profile monitor is used to measure the 2.5 MeV and 14 MeV neutron emission line integrals before and after sawtooth crashes in high d-d neutron yield, hot ion H mode plasmas in the Joint European Torus (JET). Deuterium-deuterium (d-d) fusion produces 2.5 MeV neutrons and 1 MeV tritons (t) at nearly equal rates from its two reaction channels. A plasma current of 3 MA is sufficiently high to contain most of the fusion product tritons, which have birth orbit gyroradii and velocity space distributions similar to those of the 3.5 MeV or particles from d-t fusion. By examining neutron emission line integrals and tomographically deduced local emissivity profiles, an upper limit of 10% can be placed on the net fraction of fusion product tritons which are displaced from the plasma axis by those sawtooth crashes studied. This is a much smaller net fraction than that typically observed, 35-55%, for displaced injected neutral beam deuterium ions. A study of the response of beam injected deuterium ions to a sawtooth crash shows that the change in their axial density depends on the precrash spatial width of the neutron emissivity profile. The fusion product tritons, which have a large precrash spatial width, respond weakly to a crash. This weak response is consistent with the behaviour of the analogous d-d beam thermal neutrons when extrapolated to the corresponding emissivity spatial width. The implication of these observations is that beam ions and 3.5 MeV alpha particles in JET may be relatively resilient to sawtooth clashes, when the spatial width of their density is sufficiently large

  10. Polyaniline-based nickel electrodes for electrochemical supercapacitors-Influence of Triton X-100

    NASA Astrophysics Data System (ADS)

    Girija, T. C.; Sangaranarayanan, M. V.

    The influence of Triton X-100 in enhancing the capacitance of polyaniline-based nickel electrodes is reported. Cyclic voltammetric experiments, galvanostatic charge-discharge studies and impedance analysis were carried out in order to investigate the applicability of the system as an electrochemical supercapacitor. A qualitative interpretation of the enhancement is provided. Fourier transform infrared (FTIR), X-ray diffraction and scanning electron microscopy techniques were employed for characterization of the electrode.

  11. Long-Wavelength-Absorbing Forms of Bacteriochlorophyll a in Solutions of Triton X-100

    NASA Astrophysics Data System (ADS)

    Gottstein, J.; Scheer, H.

    1983-04-01

    At leat three forms of Triton X-100-solubilized bacteriochlorophyll a (BChl a) have been characterized by UV/visible/near-IR absorption and CD spectra. One, absorbing at 770 nm, is similar to a monomeric solution in methanol. The two others have strongly red-shifted absorption peaks (860 nm and 930, 835 nm) and intense and complex CD bands in this region, indicative of strong interaction of at least two and three molecules of BChl a, respectively.

  12. Astrometry of Single-Chord Occultations: Application to the 1993 Triton Event

    NASA Technical Reports Server (NTRS)

    Olkin, Catherine B.; Elliot, J. L.; Bus, Schelte J.; McDonald, Stephen W.; Dahn, Conrad C.

    1996-01-01

    This paper outlines a method for reducing astrometric data to derive the closest approach time and distance to the center of an occultation shadow for a single observer. The method applies to CCD frames, strip scans or photographic plates and uses a set of field stars of unknown positions to define a common coordinate system for all frames. The motion of the occulting body is used to establish the transformation between this common coordinate system and the celestial coordinate system of the body's ephemeris. This method is demonstrated by application to the Tr6O occultation by Triton on 1993 July 10 UT. Over an interval of four nights that included the occultation time, 80 frames of Triton and Tr6O were taken near the meridian with the U.S. Naval Observatory (USNO) 61-inch astrometric reflector. Application of the method presented here to these data yields a closest approach distance of 359 +/- 133 km (corresponding to 0.017 +/- 0.006 arcsec) for the occultation chord obtained with the Kuiper Airborne Observatory (KAO). Comparison of the astrometric closest approach time with the KAO light-curve midtime shows a difference of 2.2 +/- 4.1 s. Relative photometry of Triton and Tr6O, needed for photometric calibration of the occultation light curve, is also presented.

  13. Influence of rhamnolipids and Triton X-100 on adsorption of phenol by Penicillium simplicissimum.

    PubMed

    Liu, Zhifeng; Zeng, Zhuotong; Zeng, Guangming; Li, Jianbing; Zhong, Hua; Yuan, Xingzhong; Liu, Yang; Zhang, Jiachao; Chen, Ming; Liu, Yuanyuan; Xie, Gengxin

    2012-04-01

    The effects of rhamnolipids and Triton X-100 on phenol adsorption by Penicillium simplicissimum were studied. The optimum pH was 7 for phenol adsorption by all the test biomasses. The adsorption of phenol at pH 7 by biomass pre-treated with 0.05% Triton X-100, 0.2% Triton X-100, 0.05% rhamnolipids and 0.005% rhamnolipids was 3.4, 2.7, 2.4, and 1.8-fold, respectively, that of untreated biomass. The pseudo-second-order model and the Freundlich isotherms described the adsorption processes better than the pseudo-first-order model and the Langmuir isotherms, respectively. The pre-treatments by surfactants increased the zeta potential and hydrophobicity of P. simplicissimum. Analysis of the cell surface by Fourier transform infrared spectrometry, energy dispersive X-ray, and environmental scanning electron microscopy indicated that the pre-treatments by surfactants changed the cell surface functional groups, element concentrations and micrographs. The results indicated that surfactants can be potentially used to increase phenol adsorption. PMID:22326331

  14. Simulated rainfall-driven dissolution of TNT, Tritonal, Comp B and Octol particles.

    PubMed

    Taylor, Susan; Lever, James H; Fadden, Jennifer; Perron, Nancy; Packer, Bonnie

    2009-05-01

    Live-fire military training can deposit millimeter-sized particles of high explosives (HE) on surface soils when rounds do not explode as intended. Rainfall-driven dissolution of the particles then begins a process whereby aqueous HE solutions can enter the soil and groundwater as contaminants. We dripped water onto individual particles of TNT, Tritonal, Comp B and Octol to simulate how surface-deposited HE particles might dissolve under the action of rainfall and to use the data to verify a model that predicts HE dissolution as a function of particle size, particle composition and rainfall rate. Particle masses ranged from 1.1 to 17 mg and drip rates corresponded to nominal rainfall rates of 6 and 12 mmh(-1). For the TNT and Tritonal particles, TNT solubility governed dissolution time scales, whereas the lower-solubility of RDX controlled the dissolution time of both RDX and TNT in Comp B. The large, low-solubility crystals of HMX slowed but did not control the dissolution of TNT in Octol. Predictions from a drop-impingement dissolution model agree well with dissolved-mass timeseries for TNT, Tritonal and Comp B, providing some confidence that the model will also work well when applied to the rainfall-driven, outdoor dissolution of these HE particles. PMID:19215963

  15. New Constraints on the Small Kuiper Belt Object Population from High-Resolution Images of Triton

    NASA Astrophysics Data System (ADS)

    McKinnon, W. B.; Schenk, P. M.; Stern, S. A.

    Triton serves as an effective witness plate for Kuiper belt objects due to Triton's proximity to the Kuiper Belt and relatively young surface. Stern and McKinnon (LPSC XXX, abs. #1766, 1999; AJ 119, 945-952, 2000) showed Triton's crater populations to be consistent with a population of sub-km Kuiper belt objects with an approximately b = -3 differential power-law size index, dominance of KBO over Oort cloud impactors, and surface ages under 0.5 Ga. Here we update these findings based on the 10-frame highest resolution image sequence taken by Voyager 2 in 1989, not included in our earlier work. These images suffer degrees of image smear due to uncompensated spacecraft motion, but with careful processing and analysis, meaningful crater counts can be extracted. We focus on regions of abundant and easily discriminated primary craters, such as Cipango Planum (10o N, 35o E), a nearly featureless, rolling volcanic plain. There, craters can be confidently identified down to 1 km diameter, implying Kuiper Belt impactors below 100 m in diameter. The corresponding crater size-frequency index in the 1-to-6 km diameter range is similar to slightly steeper than that for more global counts at larger sizes, but remains consistent with b = -3.

  16. The Effect of Triton X-100 on Biodegradation of Aliphatic and Aromatic Fractions of Crude Oil in Soil

    NASA Astrophysics Data System (ADS)

    Minai-Tehrani, Dariush; Minooi, Saiid; Azari-Dehkordi, Forood; Herfatmanesh, Ali

    Crude oil is one the most common organic pollutant of the soil. The spillage of crude oil in the soil can be harmful to living organisms. Certain microorganisms are able to biodegrade crude oil and use it as sole carbon source. Some detergents were used to help the biodegradation of crude oil by microorganisms. In this study Triton X-100 was used to determine its effect in biodegradation of aliphatic and aromatic fractions of heavy crude oil in soil during 4 months. Different concentration of Triton X-100 (0 to 0.25%) was added to crude oil-contaminated soil with 2% (w/w) crude oil as final concentration. Present results demonstrated that in 0.025% of Triton X-100 the reduction of total crude oil, total aliphatic and total aromatic fractions were high, while in 0.05 to 0.25% the reduction reached to its minimum value. The higher reduction of phenanthrene, anthracene, fluoranthene and pyrene was observed in 0.025% Triton X-100 while it was lower in 0.25% followed by 0.1% Triton X-100. The low reduction of C17/pristane and C18/phytane in 0.25% Triton X-100 suggested low bioavaibility of aliphatic compounds in this concentration.

  17. Role of solubilized water in micelles formed by Triton X-100 in 1-butyl-3-methylimidazolium ionic liquids.

    PubMed

    Li, Na; Zhang, Shaohua; Ma, Hongchao; Zheng, Liqiang

    2010-06-15

    We demonstrate here the aggregation behavior of a nonionic surfactant Triton X-100 in two 1-butyl-3-methylimidazolium ionic liquids (the hydrophilic IL [bmim][BF(4)] and the hydrophobic IL [bmim][PF(6)]) by surface tension measurements. The effects of added water on the microstructure of Triton X-100 in ILs micelles are investigated. When small amounts of water are added to Triton X-100 in [bmim][PF(6)] micelles, the water molecules are first bound to the ethylene oxide (EO) units of Triton X-100 and then form the water pool in the core of the microemulsion. When water molecules are added to the Triton X-100 in [bmim][BF(4)] micelles, there is no microemulsion formed; these water molecules are first solubilized in [bmim][BF(4)]. When the solubilization is saturated, the water molecules start to bind to the EO group of Triton X-100; these results are confirmed by UV-vis, FTIR, and (1)H NMR spectra. PMID:20302278

  18. Misalignment in Gas Foil Journal Bearings: An Experimental Study

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2008-01-01

    As gas foil journal bearings become more prevalent in production machines, such as small gas turbine propulsion systems and microturbines, system-level performance issues must be identified and quantified in order to provide for successful design practices. Several examples of system-level design parameters that are not fully understood in foil bearing systems are thermal management schemes, alignment requirements, balance requirements, thrust load balancing, and others. In order to address some of these deficiencies and begin to develop guidelines, this paper presents a preliminary experimental investigation of the misalignment tolerance of gas foil journal bearing systems. Using a notional gas foil bearing supported rotor and a laser-based shaft alignment system, increasing levels of misalignment are imparted to the bearing supports while monitoring temperature at the bearing edges. The amount of misalignment that induces bearing failure is identified and compared to other conventional bearing types such as cylindrical roller bearings and angular contact ball bearings. Additionally, the dynamic response of the rotor indicates that the gas foil bearing force coefficients may be affected by misalignment.

  19. Foil dissociation of fast molecular ions into atomic excited states

    SciTech Connect

    Berry, H.G.; Gay, T.J.; Brooks, R.L.

    1980-01-01

    The intensity and polarizations of light emitted from atomic excited states of dissociated molecular ions were measured. The dissociations are induced when fast molecular ions (50 to 500 keV/amu) are transmitted through thin carbon foils. A calculation of multiple scattering and the Coulomb explosion gives the average internuclear separation of the projectile at the foil surface. Experimentally, the foil thickness is varied to give varying internuclear separations at the foil surface and observe the consequent variation in light yield and optical polarization. Using HeH/sup +/ projectiles, factors of 1 to 5 enhancements of the light yields from n = 3, /sup 1/ /sup 3/P,D states of He I and some He II and H I emissions were observed. The results can be explained in terms of molecular level crossings which provide mixings of the various final states during dissociation of the molecular ions at the exit surface. They suggest a short range surface interaction of the electron pick-up followed by a slow molecular dissociation. Alignment measurements confirm the essential features of the model. Observations of Lyman ..cap alpha.. emission after dissociation of H/sub 2//sup +/ amd H/sub 3//sup +/ show rapid variations in light yield for small internuclear separations at the foil surface.

  20. Iridium and tantalum foils for spaceflight neutron dosimetry.

    NASA Technical Reports Server (NTRS)

    English, R. A.; Liles, E. D.

    1972-01-01

    Description of a two-foil system of iridium and tantalum which can measure thermal and intermediate energy neutrons at flux densities of 1 neutron/sq cm-sec over a ten-day lunar mission (1,000,000 neutrons/sq cm). The foils are chemically inert and nontoxic, weigh less than 1 g each, and require only routine gamma pulse height analysis for activation measurement. Detection of fluences below 1,000,000 neutrons/sq cm are achieved for counts of foil activity made as late as two months following neutron exposure. Tantalum foils flown in Apollo 11 indicated a mean dose equivalent to the astronauts of less than 16 mrem from thermal plus intermediate energy neutrons, while nuclear emulsion track analysis indicated approximately 17 mrem from neutrons of energy greater than 0.6 MeV. Iridium foils flown on Apollo 12 indicated dose equivalents of 1.8 to 2.8 mrem from thermal neutrons, excluding tissue thermalized SNAP-27 neutrons.

  1. Gas Foil Bearings for Space Propulsion Nuclear Electric Power Generation

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; DellaCorte, Christopher

    2006-01-01

    The choice of power conversion technology is critical in directing the design of a space vehicle for the future NASA mission to Mars. One candidate design consists of a foil bearing supported turbo alternator driven by a helium-xenon gas mixture heated by a nuclear reactor. The system is a closed-loop, meaning there is a constant volume of process fluid that is sealed from the environment. Therefore, foil bearings are proposed due to their ability to use the process gas as a lubricant. As such, the rotor dynamics of a foil bearing supported rotor is an important factor in the eventual design. The current work describes a rotor dynamic analysis to assess the viability of such a system. A brief technology background, assumptions, analyses, and conclusions are discussed in this report. The results indicate that a foil bearing supported turbo alternator is possible, although more work will be needed to gain knowledge about foil bearing behavior in helium-xenon gas.

  2. Flapping Instability of Two Tandem Flexible Foils in Uniform Axial Flow

    NASA Astrophysics Data System (ADS)

    Gurugubelli, Pardha Saradhi; Jaiman, Rajeev Kumar; Chua, Cassey

    2015-11-01

    We present a numerical analysis on the stability and coupled dynamics of two tandem flexible foils clamped at their leading edges in a uniform axial flow. The flexible foils considered for this study correspond to the fixed-point stable regime of the single flexible foil where the flexible foil aligns itself in the flow direction with no significant trailing edge oscillations. A high-order nonlinear coupled solver based on the variational formulation has been considered for analyzing the effects of gap between the foils on the stability and coupled behaviour of both the upstream and downstream foils. As a function of decreasing gap, it is observed that the tandem foil configuration is more prone to flapping instability than its single flexible foil counterpart. The evolution of the instability for the downstream foil shows two distinct dynamical scenarios: (i) only the downstream foil exhibits flapping motion and (ii) both the upstream and the downstream foils perform flapping. With the aid of a rigid foil in the upstream of a flexible foil, we further present a detailed analysis on the effects of the upstream wake and vortex shedding on the stability and flapping dynamics of the downstream foil.

  3. ICE MINERALOGY ACROSS AND INTO THE SURFACES OF PLUTO, TRITON, AND ERIS

    SciTech Connect

    Tegler, S. C.; Grundy, W. M.; Olkin, C. B.; Young, L. A.; Romanishin, W.; Cornelison, D. M.; Khodadadkouchaki, R. E-mail: W.Grundy@lowell.edu E-mail: layoung@boulder.swri.edu E-mail: DavidCornelison@MissouriState.edu

    2012-05-20

    We present three near-infrared spectra of Pluto taken with the Infrared Telescope Facility and SpeX, an optical spectrum of Triton taken with the MMT and the Red Channel Spectrograph, and previously published spectra of Pluto, Triton, and Eris. We combine these observations with a two-phase Hapke model and gain insight into the ice mineralogy on Pluto, Triton, and Eris. Specifically, we measure the methane-nitrogen mixing ratio across and into the surfaces of these icy dwarf planets. In addition, we present a laboratory experiment that demonstrates it is essential to model methane bands in spectra of icy dwarf planets with two methane phases-one highly diluted by nitrogen and the other rich in methane. For Pluto, we find bulk, hemisphere-averaged, methane abundances of 9.1% {+-} 0.5%, 7.1% {+-} 0.4%, and 8.2% {+-} 0.3% for sub-Earth longitudes of 10 Degree-Sign , 125 Degree-Sign , and 257 Degree-Sign . Application of the Wilcoxon rank sum test to our measurements finds these small differences are statistically significant. For Triton, we find bulk, hemisphere-averaged, methane abundances of 5.0% {+-} 0.1% and 5.3% {+-} 0.4% for sub-Earth longitudes of 138 Degree-Sign and 314 Degree-Sign . Application of the Wilcoxon rank sum test to our measurements finds the differences are not statistically significant. For Eris, we find a bulk, hemisphere-averaged, methane abundance of 10% {+-} 2%. Pluto, Triton, and Eris do not exhibit a trend in methane-nitrogen mixing ratio with depth into their surfaces over the few centimeter range probed by these observations. This result is contrary to the expectation that since visible light penetrates deeper into a nitrogen-rich surface than the depths from which thermal emission emerges, net radiative heating at depth would drive preferential sublimation of nitrogen leading to an increase in the methane abundance with depth.

  4. Titan's photochemical model: Further update, oxygen species, and comparison with Triton and Pluto

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, V. A.

    2012-12-01

    The photochemical model for Titan's atmosphere and ionosphere is improved using the Troe approximation for termolecular reactions and inclusion of four radiative association reactions from those calculated by Vuitton et al. (2012). Proper fitting of eddy diffusion results in a reduction of the mean difference between 63 observed mixing ratios and their calculated values from a factor of 5 in our previous Titan's models to a factor of 3 in the current model. Oxygen chemistry on Titan is initiated by influxes of H2O from meteorites and O+ from magnetospheric interactions with the Saturn rings and Enceladus. Two versions of the model were calculated, with and without the O+ flux. Balances of CO, CO2, H2O, and H2CO are discussed in detail for both versions. The calculated model with the O+ flux agrees with the observations of CO, CO2, and H2O, including recent H2O CIRS limb observations and measurements by the Herschel Space Observatory. Major observational data and photochemical models for Triton and Pluto are briefly discussed. While the basic atmospheric species N2, CH4, and CO are similar on Triton and Pluto, properties of their atmospheres are very different with dominating atomic species and ions in Triton's upper atmosphere and ionosphere opposed to the molecular composition on Pluto. Calculations favor a transition between two types of photochemistry at the CH4 mixing ratio of ~5×10-4. Therefore the current Triton's photochemistry is still similar to that at the Voyager flyby despite the observed increase in N2 and CH4. The meteorite H2O results in precipitation of CO on Triton and CO2 on Pluto near perihelion. Main oxygen species on Titan: observations and the model. Solid lines show the model with both meteorite influx of H2O and magnetospheric flux of O+. Thin lines show the model without flux of O+. Observations: (1) CIRS (de Kok et al. 2007), (2) CIRS at 5°N (Vinatier et al. 2010), (3) ISO (Coustenis et al. 1998), (4) INMS (Cui et al., 2009), (5) CIRS

  5. Nanowire LEDs grown directly on flexible metal foil

    NASA Astrophysics Data System (ADS)

    May, Brelon J.; Sarwar, A. T. M. Golam; Myers, Roberto C.

    2016-04-01

    Using molecular beam epitaxy, self-assembled AlGaN nanowires are grown directly on Ta and Ti foils. Scanning electron microscopy shows that the nanowires are locally textured with the underlying metallic grains. Photoluminescence spectra of GaN nanowires grown on metal foils are comparable to GaN nanowires grown on single crystal Si wafers. Similarly, photoluminescence lifetimes do not vary significantly between these samples. Operational AlGaN light emitting diodes are grown directly on flexible Ta foil with an electroluminescence peak emission of ˜350 nm and a turn-on voltage of ˜5 V. These results pave the way for roll-to-roll manufacturing of solid state optoelectronics.

  6. Laser shock microforming of aluminum foil with fs laser

    NASA Astrophysics Data System (ADS)

    Ye, Yunxia; Feng, Yayun; Xuan, Ting; Hua, Xijun; Hua, Yinqun

    2014-12-01

    Laser shock microforming of Aluminum(Al) foil through fs laser has been researched in this paper. The influences of confining layer, clamping method and impact times on induced dent depths were investigated experimentally. Microstructure of fs laser shock forming Al foil was observed through Transmission electron microscopy (TEM). Under the condition of tightly clamping, the dent depths increase with impact times and finally tend to saturating. Another new confining layer, the main component of which is polypropylene, was applied and the confining effect of it is better because of its higher impedance. TEM results show that dislocation is one of the main deformation mechanisms of fs laser shock forming Al foil. Specially, most of dislocations exist in the form of short and discrete dislocation lines. Parallel straight dislocation slip line also were observed. We analyzed that these unique dislocation arrangements are due to fs laser-induced ultra high strain rate.

  7. Model-Based Optimization for Flapping Foil Actuation

    NASA Astrophysics Data System (ADS)

    Izraelevitz, Jacob; Triantafyllou, Michael

    2014-11-01

    Flapping foil actuation in nature, such as wings and flippers, often consist of highly complex joint kinematics which present an impossibly large parameter space for designing bioinspired mechanisms. Designers therefore often build a simplified model to limit the parameter space so an optimum motion trajectory can be experimentally found, or attempt to replicate exactly the joint geometry and kinematics of a suitable organism whose behavior is assumed to be optimal. We present a compromise: using a simple local fluids model to guide the design of optimized trajectories through a succession of experimental trials, even when the parameter space is too large to effectively search. As an example, we illustrate an optimization routine capable of designing asymmetric flapping trajectories for a large aspect-ratio pitching and heaving foil, with the added degree of freedom of allowing the foil to move parallel to flow. We then present PIV flow visualizations of the optimized trajectories.

  8. Dynamics of a heaving flexible foil in a uniform flow

    NASA Astrophysics Data System (ADS)

    Paraz, Florine; Eloy, Christophe; Schouveiler, Lionel

    2012-11-01

    Most aerial and aquatic animals produce thrust using flapping flexible appendages. The performances of such propulsion systems are strongly related to the appendages dynamics, in particular to the amplitude of the trailing edge motion and to the vortical patterns produced. A better understanding of this mode of propulsion requires to investigate the dynamics of the flexible appendages, as a response to harmonic forcing. In this context, experiments are performed with flexible foils immersed in the uniform flow of a water channel. A harmonic heaving motion, that is transverse to the foil, is then imposed to its leading edge. The response of the foil likely results from the resonance between the forcing and the natural modes of vibration. Experimental results are compared with a two-dimensional model assuming a zero-thickness flexible sheet of infinite span immersed in a potential flow.

  9. An experimental and theoretical study of structural damping in compliant foil bearings

    NASA Technical Reports Server (NTRS)

    Ku, C.-P. Roger

    1994-01-01

    This paper describes an experimental investigation into the dynamic characteristics of corrugated foil (bump foil) strips used in compliant surface foil bearings. This study provided and opportunity to quantify the structural damping of bump foil strips. The experimental data were compared to results obtained by a theoretical model developed earlier. The effects of bearing design parameters, such as static loads, dynamic displacement amplitudes, bump configurations, pivot locations, surface coatings, and lubricant were also evaluated. An understanding of the dynamic characteristics of bump foil strips resulting from this work offers designers a means for enhancing the design of high-performance compliant foil bearings.

  10. High Temperature Performance Evaluation of a Compliant Foil Seal

    NASA Technical Reports Server (NTRS)

    Salehi, Mohsen; Heshmat, Hooshang; Walton, James F., II

    2001-01-01

    The key points to be gleaned from the effort reported herein are that the CFS (Compliant Foil Seal) has been demonstrated in conjunction with a foil bearing in a small gas turbine simulator at temperatures as high as 1000 F and outperformed a comparable brush seal. Having demonstrated the feasibility of the CFS, it would appear that this new seal design has application potential in a wide range of machines. What remains is to demonstrate performance at higher pressure ratios, consistent performance at large rotor excursions and the ability to manufacture the seal in much larger sizes exceeding by an order of magnitude that which has been tested to date.

  11. Effect of Smoked Foil Thickness and Location on Detonation Initiation

    NASA Astrophysics Data System (ADS)

    Chung, K. M.; Wen, C. S.

    Smoked foil has been employed to visualize triple point pattern (or cell width), indicating detonation phenomena. However, the aluminum sheet also corresponds to sudden contraction in a smooth tube. It might induce early trigger on detonation initiation and result in a reduction in deflagration-to-detonation transition (DDT) run-up distance. Test results showed the thickness of aluminum sheet of less than 1.3 mm is required to eliminate the effect of smoked foil. A reduction in Xdtt is observed when the thickness of aluminum sheet increases.

  12. Method and apparatus for tensile testing of metal foil

    NASA Technical Reports Server (NTRS)

    Wade, O. W. (Inventor)

    1976-01-01

    A method for obtaining accurate and reproducible results in the tensile testing of metal foils in tensile testing machines is described. Before the test specimen are placed in the machine, foil side edges are worked until they are parallel and flaw free. The specimen are also aligned between and secured to grip end members. An aligning apparatus employed in the method is comprised of an alignment box with a longitudinal bottom wall and two upright side walls, first and second removable grip end members at each end of the box, and a means for securing the grip end members within the box.

  13. Electrochemically replicated smooth aluminum foils for anodic alumina nanochannel arrays.

    PubMed

    Biring, Sajal; Tsai, Kun-Tong; Sur, Ujjal Kumar; Wang, Yuh-Lin

    2008-01-01

    A fast electrochemical replication technique has been developed to fabricate large-scale ultra-smooth aluminum foils by exploiting readily available large-scale smooth silicon wafers as the masters. Since the adhesion of aluminum on silicon depends on the time of surface pretreatment in water, it is possible to either detach the replicated aluminum from the silicon master without damaging the replicated aluminum and master or integrate the aluminum film to the silicon substrate. Replicated ultra-smooth aluminum foils are used for the growth of both self-organized and lithographically guided long-range ordered arrays of anodic alumina nanochannels without any polishing pretreatment. PMID:21730530

  14. Surface plasma wave excitation via laser irradiated overdense plasma foil

    SciTech Connect

    Kumar, Pawan; Tripathi, V. K.

    2012-04-09

    A laser irradiated overdense plasma foil is seen to be susceptible to parametric excitation of surface plasma wave (SPW) and ion acoustic wave (IAW) on the ion plasma period time scale. The SPW is localised near the front surface of the foil while IAW extends upto the rear. The evanescent laser field and the SPW exert a ponderomotive force on electrons driving the IAW. The density perturbation associated with the latter beats with the laser induced oscillatory electron velocity to drive the SPW. At relativistic laser intensity, the growth rate is of the order of ion plasma frequency.

  15. Tidal interaction: A possible explanation for geysers and other fluid phenomena in the Neptune-Triton system

    NASA Technical Reports Server (NTRS)

    Kelly, W. D.; Wood, C. L.

    1993-01-01

    Discovery of geyser-like plumes on the surface of Triton was a highlight of Voyager 2's passage through the Neptune planetary system. Remarkable as these observations were, they were not entirely without precedent. Considering the confirmed predictions for the 1979 Voyager Jovian passage, it was logical to consider other solar system bodies beside Io where tidal effects could be a significant factor in surface processes. It was our intuition that the Neptune-Triton gravitational bond acting at high inclination to the Neptune equator and the fact that Neptune was a fluid body was significant oblateness would produce tidal and mechanical forces that could be transformed into thermal energy vented on Triton's surface. Prior to the Voyager flyby, others have noted that capture and evolution of Triton's orbit from extreme eccentricity to near circular state today would have resulted in significant tidal heating, but these analysts disregard current day forces. Our calculations indicate that the time varying forces between Neptune-Triton fall midway between those exerted in the Earth-Moon and Jupiter-Io systems, and considering the low level of other energy inputs, this source of internal energy should not be ignored when seeking an explanation for surface activity. In each planet-satellite case, residual or steady-state eccentricity causes time-varying stresses on internal satellite strata. In the case of Jupiter the residual eccentricity is due largely to Galilean satellite interactions, particularly Io-Europa, but in the case of Neptune-Triton, it is the effect of Triton's inclined orbit about an oblate primary.

  16. Design, Fabrication and Performance of Open Source Generation I and II Compliant Hydrodynamic Gas Foil Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Radil, Kevin C.; Bruckner, Robert J.; Howard, S. Adam

    2007-01-01

    Foil gas bearings are self-acting hydrodynamic bearings made from sheet metal foils comprised of at least two layers. The innermost top foil layer traps a gas pressure film that supports a load while a layer or layers underneath provide an elastic foundation. Foil bearings are used in many lightly loaded, high-speed turbo-machines such as compressors used for aircraft pressurization, and small micro-turbines. Foil gas bearings provide a means to eliminate the oil system leading to reduced weight and enhanced temperature capability. The general lack of familiarity of the foil bearing design and manufacturing process has hindered their widespread dissemination. This paper reviews the publicly available literature to demonstrate the design, fabrication and performance testing of both first and second generation bump style foil bearings. It is anticipated that this paper may serve as an effective starting point for new development activities employing foil bearing technology.

  17. Energy harvesting through flow-induced oscillations of a foil

    NASA Astrophysics Data System (ADS)

    Peng, Zhangli; Zhu, Qiang

    2009-12-01

    By using a Navier-Stokes model, we examine a novel flow energy harvesting device consisting of a flapping foil mounted on a damper (representing the power generator) and a rotational spring. Self-induced and self-sustained flapping motions, including a heaving motion h(t ) and a pitching motion α(t ), are excited by an incoming flow and power extraction is achieved from the heaving response. Depending upon the configuration of the system and the mechanical parameters (e.g., the location of the pitching axis and the stiffness of the rotational spring), four different responses are recorded: (i) the foil remains stable in its initial position (α =0 and h =0); (ii) periodic pitching (around α =0) and heaving motions are excited; (iii) the foil undergoes irregular motions characterized by switching between oscillations around two pitching angles; and (iv) the foil rotates to a position with an angle to the incoming flow and oscillates around it. The existence of response (ii) suggests the feasibility of controllable and stable flow energy extraction by this device. Through numerical simulations with a Navier-Stokes model we have determined combinations of geometric and mechanical parameters to achieve this response. The corresponding energy harvesting capacity and efficiency are predicted.

  18. Tribalism as a Foiled Factor of Africa Nation-Building

    ERIC Educational Resources Information Center

    Okogu, J. O.; Umudjere, S. O.

    2016-01-01

    This paper tends to examine tribalism as a foiled factor on Africa nation-building and proffers useful tips to salvaging the Africa land from this deadly social problem. Africans in times past had suffered enormous attacks, injuries, losses, deaths, destruction of properties and human skills and ideas due to the presence of tribalistic views in…

  19. The Visualization of Infrared Radiation Using Thermal Sensitive Foils

    ERIC Educational Resources Information Center

    Bochnícek, Zdenek

    2013-01-01

    This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 µm of wavelength can be detected. The…

  20. Using Aluminum Foil to Record Structures in Sedimentary Rock.

    ERIC Educational Resources Information Center

    Metz, Robert

    1982-01-01

    Aluminum foil can be used to make impressions of structures preserved in sedimentary rock. The impressions can be projected onto a screen, photographed, or a Plaster of Paris model can be made from them. Impressions of ripple marks, mudcracks, and raindrop impressions are provided in photographs illustrating the technique. (Author/JN)

  1. Laser-induced structure formation on stretched polymer foils

    SciTech Connect

    Bityurin, Nikita; Arnold, Nikita; Baeuerle, Dieter; Arenholz, Enno

    2007-04-15

    Noncoherent structures that develop during UV laser ablation of stretched semicrystalline polymer foils are a very general phenomenon. A thermodynamic model based on stress relaxation within the modified layer of the polymer surface describes the main features of the observed phenomena, and, in particular, the dependence of the period of structures on laser wavelength, fluence, and number of laser pulses.

  2. Foil Bearing Starting Considerations and Requirements for Rotorcraft Engine Applications

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2009-01-01

    Foil gas bearings under development for rotorcraft-sized, hot core engine applications have been susceptible to damage from the slow acceleration and rates typically encountered during the pre-ignition stage in conventional engines. Recent laboratory failures have been assumed to be directly linked to operating foil bearings below their lift-off speed while following conventional startup procedures for the engines. In each instance, the continuous sliding contact between the foils and shaft was believed to thermally overload the bearing and cause the engines to fail. These failures highlight the need to characterize required acceleration rates and minimum operating speeds for these applications. In this report, startup experiments were conducted with a large, rotorcraft engine sized foil bearing under moderate load and acceleration rates to identify the proper start procedures needed to avoid bearing failure. The results showed that a bearing under a 39.4 kPa static load can withstand a modest acceleration rate of 500 rpm/s and excessive loitering below the bearing lift-off speed provided an adequate solid lubricant is present.

  3. Validation of calculated self-shielding factors for Rh foils

    NASA Astrophysics Data System (ADS)

    Jaćimović, R.; Trkov, A.; Žerovnik, G.; Snoj, L.; Schillebeeckx, P.

    2010-10-01

    Rhodium foils of about 5 mm diameter were obtained from IRMM. One foil had thickness of 0.006 mm and three were 0.112 mm thick. They were irradiated in the pneumatic transfer system and in the carousel facility of the TRIGA reactor at the Jožef Stefan Institute. The foils were irradiated bare and enclosed in small cadmium boxes (about 2 g weight) of 1 mm thickness to minimise the perturbation of the local neutron flux. They were co-irradiated with 5 mm diameter and 0.2 mm thick Al-Au (0.1%) alloy monitor foils. The resonance self-shielding corrections for the 0.006 and 0.112 mm thick samples were calculated by the Monte Carlo simulation and amount to about 10% and 60%, respectively. The consistency of measurements confirmed the validity of self-shielding factors. Trial estimates of Q0 and k0 factors for the 555.8 keV gamma line of 104Rh were made and amount to 6.65±0.18 and (6.61±0.12)×10 -2, respectively.

  4. Characterization of thin-foil ultracold neutron detectors

    NASA Astrophysics Data System (ADS)

    Sallaska, A. L.; Hoedl, S.; Garcia, A.; Melconian, D.; Young, A. R.; Geltenbort, P.; Sjue, S. K. L.; Holley, A. T.

    2009-05-01

    We have fabricated ultracold neutron detectors that consist of silicon charged particle detectors coupled with thin nickel foils coated with either natural LiF or 10B implanted into vanadium. The foils convert neutrons into energetic, readily detectable, charged particles which are in turn detected by silicon detectors. The detectors were tested at the Institut Laue-Langevin with a gravitational spectrometer. From a rigorous Monte Carlo simulation of the experiment, the minimum detection cutoff velocities (effective potentials) were determined to be 309±17 cm/s ( 49.8±2.7 neV) for LiF and 367±39 cm/s ( 70.3±7.5 neV) for 10B/V. Although the result for LiF is consistent with expectations, the result for 10B/V is significantly higher. We interpret this discrepancy as due to contamination. We also show that while a thicker foil is more efficient for ultracold neutron detection, a thinner foil is more ideal for determining the cutoff velocity.

  5. Secret in the Margins: Rutherford's Gold Foil Experiment

    ERIC Educational Resources Information Center

    Aydin, Sevgi; Hanuscin, Deborah L.

    2011-01-01

    In this article, the authors describe a lesson that uses the 5E Learning Cycle to help students not only understand the atomic model but also how Ernest Rutherford helped develop it. The lesson uses Rutherford's gold foil experiment to focus on three aspects of the nature of science: the empirical nature of science, the tentativeness of scientific…

  6. Proton acceleration from short pulse lasers interacting with ultrathin foil

    NASA Astrophysics Data System (ADS)

    Petrov, George; McGuffey, Christopher; Thomas, Alec; Krushelnick, Karl; Beg, Farhat

    2015-11-01

    Two-dimensional particle-in-cell simulations using 50 nm Si3N4 and DLC foils are compared to published experimental data of proton acceleration from ultra-thin foils (<1 μm) irradiated by short pulse lasers (30-50 fs), and some underlying physics issues pertinent to proton acceleration have been addressed. 2D particle-in-cell simulations show that the maximum proton energy scales as I2/3, stronger than Target Normal Sheath Acceleration for thick foils (>1 μm), which is typically between I1/3 and I1/2. Published experimental data were found to depend primarily on the laser energy and scale as E2/3. The different scaling laws for thick (>1 μm) and ultra-thin (<1 μm) foils are explained qualitatively as transitioning from Target Normal Sheath Acceleration to more advanced acceleration schemes such as Radiation-Induced Transparency and Radiation Pressure Acceleration regimes. This work was performed with the support of the Air Force Office of Scientific Research under grant FA9550-14-1-0282.

  7. Modified Monkman-Grant relationship for austenitic stainless steel foils

    NASA Astrophysics Data System (ADS)

    Osman Ali, Hassan; Tamin, Mohd Nasir

    2013-02-01

    Characteristics of creep deformation for austenitic stainless steel foils are examined using the modified Monkman-Grant equation. A series of creep tests are conducted on AISI 347 steel foils at 700 °C and different stress levels ranging from 54 to 221 MPa. Results showed that at lower stress levels below 110 MPa, the creep life parameters ɛ, ɛr, tr can be expressed using the modified Monkman-Grant equation with exponent m'= 0.513. This indicates significant deviation of the creep behavior from the first order reaction kinetics theory for creep (m' = 1.0). The true tertiary creep damage in AISI 347 steel foil begins after 65.9% of the creep life of the foil has elapsed at stress levels above 150 MPa. At this high stress levels, Monkman-Grant ductility factor λ' saturates to a value of 1.3 with dislocation-controlled deformation mechanisms operating. At low stress levels, λ' increases drastically (λ'=190 at 54 MPa) when slow diffusion-controlled creep is dominant.

  8. Foil bearing performance in liquid nitrogen and liquid oxygen

    NASA Technical Reports Server (NTRS)

    Genge, Gary G.; Saville, Marshall; Gu, Alston

    1993-01-01

    Space transfer vehicles and other power and propulsion systems require long-life turbopumps. Rolling-element bearings used in current turbopumps do not have sufficient life for these applications. Process fluid foil bearings have established long life, with exceptional reliability, over a wide range of temperatures and fluids in many high-speed turbomachinery applications. However, actual data on bearing performance in cryogenic fluids has been minimal. The National Aeronautics and Space Administration (NASA) and AlliedSignal Aerospace Systems and Equipment (ASE) have attempted to characterize the leaf-type compliant foil bearing in oxygen and nitrogen. The work performed under a joint internal research and development program between Marshall Space Flight Center (MSFC) and ASE demonstrated that the foil bearing has load capacities of at least 266 psi in liquid oxygen and 352 psi in liquid nitrogen. In addition, the bearing demonstrated a direct damping coefficient of 40 to 50 lb-sec/in. with a damping ratio of .7 to 1.4 in. liquid nitrogen using a bearing sized for upper-stage turbopumps. With the results from this testing and the years of successful use in air cycle machines and other applications, leaf-type compliant foil bearings are ready for testing in liquid oxygen turbopumps.

  9. Evaluation of Alumina-Forming Austenitic Foil for Advanced Recuperators

    SciTech Connect

    Pint, Bruce A; Brady, Michael P; Yamamoto, Yukinori; Santella, Michael L; Maziasz, Philip J; Matthews, Wendy

    2011-01-01

    A corrosion- and creep-resistant austenitic stainless steel has been developed for advanced recuperator applications. By optimizing the Al and Cr contents, the alloy is fully austenitic for creep strength while allowing the formation of a chemically stable external alumina scale at temperatures up to 900 C. An alumina scale eliminates long-term problems with the formation of volatile Cr oxy-hydroxides in the presence of water vapor in exhaust gas. As a first step in producing foil for primary surface recuperators, three commercially cast heats have been rolled to 100 m thick foil in the laboratory to evaluate performance in creep and oxidation testing. Results from initial creep testing are presented at 675 C and 750 C, showing excellent creep strength compared with other candidate foil materials. Laboratory exposures in humid air at 650 800 C have shown acceptable oxidation resistance. A similar oxidation behavior was observed for sheet specimens of these alloys exposed in a modified 65 kW microturbine for 2871 h. One composition that showed superior creep and oxidation resistance has been selected for the preparation of a commercial batch of foil. DOI: 10.1115/1.4002827

  10. Large deflection analysis of a tension-foil bearing

    NASA Technical Reports Server (NTRS)

    Elrod, David A.

    1996-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are as follows: rolling or sliding contact within the bearing has life-limiting consequences; and REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's. CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contacts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exist for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. Recently, a new tension-foil bearing configuration has been proposed for turbomachinery applications.

  11. Origin and Evolution of Nitrogen on Titan, Enceladus, Triton, and Pluto

    NASA Technical Reports Server (NTRS)

    Atreya, S. K.; Niemann, H. B.; Mahaffy, P. R.; Owen, T. C.

    2007-01-01

    Nitrogen, together with carbon, hydrogen, oxygen, phosphorus and sulfur (CHNOPS), plays a central role in life as we know it. Indeed, molecular nitrogen is the most abundant component of the terrestrial atmosphere, and second only to carbon dioxide on Mars and Venus. The Voyager and Cassini-Huygens observations show that copious nitrogen is present on Titan also, comprising some 95% by volume of this moon's 1500 millibar atmosphere. After water vapor, it may be the most abundant (4%) of the gases around tiny Enceladus, as revealed by the recent Cassini observations. A thin nitrogen atmosphere is found even on the coldest of the solar system bodies, Triton and Pluto. The available evidence on nitrogen isotopes and the heavy noble gases suggests that Titan acquired its nitrogen largely in the form of ammonia. Subsequent chemical evolution, beginning with the photolysis of NH3 on primordial Titan, led to the nitrogen atmosphere we see on Titan today. This is also the scenario for the origin of nitrogen on the terrestrial planets. Contrary to Titan, the colder outer solar system objects, Triton and Pluto, neither had the luxury of receiving much arnmonia in the first place, nor of photolyzing whatever little ammonia they did receive in the planetesimals that formed them. On the other hand, it is plausible the planetesimals were capable of trapping and delivering molecular nitrogen directly to Triton and Pluto, unlike Titan. The origin of nitrogen on Enceladus is somewhat enigmatic. A scenario similar to Titan's, but with a role for the interior processes, may be at work. In this paper, we will discuss the source and loss of nitrogen for the above objects, and why Ganymede, the largest moon in the solar system, is nitrogen starved.

  12. Solid methane on Triton and Pluto - 3- to 4-micron spectrophotometry

    SciTech Connect

    Spencer, J.R.; Buie, M.W.; Bjoraker, G.L. Space Telescope Science Institute, Baltimore, MD NASA, Goddard Space Flight Center, Greenbelt, MD )

    1990-12-01

    Methane has been identified in the Pluto/Charon system on the basis of absorption features in the reflectance spectrum at 1.5 and 2.3 microns; attention is presently given to observations of a 3.25 micron-centered deep absorption feature in Triton and Pluto/Charon system reflectance spectra. This absorption may indicate the presence of solid methane, constituting either the dominant surface species or a mixture with a highly transparent substance, such as N2 frost. 35 refs.

  13. Temperature, N2, and N density profiles of Triton's atmosphere - Observations and model

    NASA Technical Reports Server (NTRS)

    Krasnopolsky, V. A.; Sandel, B. R.; Herbert, F.; Vervack, R. J., Jr.

    1993-01-01

    Improved analysis of the Voyager Ultraviolet Spectrometer observations of the solar occultation by Triton yields the isothermal temperature and N2 number densities in the altitude range 475-675 km. The signature of atomic nitrogen in the occultation spectra is identified, its density profile is derived, and an experimental value of the escape rate of N atoms is given. The one-dimensional thermal conductivity equation for a spherical atmosphere is solved, taking into account CO heating and cooling and heating by precipitating electrons, solar radiation, and chemical effects. Finally, profiles of number densities of N, H2, and H are calculated.

  14. Temperature, N2, and N density profiles of Triton's atmosphere - Observations and model

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, V. A.; Sandel, B. R.; Herbert, F.; Vervack, R. J.

    1993-02-01

    Improved analysis of the Voyager Ultraviolet Spectrometer observations of the solar occultation by Triton yields the isothermal temperature and N2 number densities in the altitude range 475-675 km. The signature of atomic nitrogen in the occultation spectra is identified, its density profile is derived, and an experimental value of the escape rate of N atoms is given. The one-dimensional thermal conductivity equation for a spherical atmosphere is solved, taking into account CO heating and cooling and heating by precipitating electrons, solar radiation, and chemical effects. Finally, profiles of number densities of N, H2, and H are calculated.

  15. Reactivated triton-extracted models o paramecium: modification of ciliary movement by calcium ions.

    PubMed

    Naito, Y; Kaneko, H

    1972-05-01

    Triton-extracted models of Paramecium were reactivated to swim in solutions of adenosine triphosphate and magnesium ions. The cilia beat in the normal direction (toward the rear) when the calcium ion concentration was less than 10-(6)M, and they beat in the "reversed" direction (toward the front) when calcium ion concentration was raised above 10-(6)M. These results support the proposal that ciliary reversal, hence backward swimming, of live paramecia is mediated by an increased cytoplasmic calcium concentration around the ciliary system by calcium-dependent membrane responses to external stimuli. PMID:5032354

  16. 21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Tin-coated lead foil capsules for wine bottles... Addition to Human Food Through Food-Contact Surfaces § 189.301 Tin-coated lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one or both sides with a thin...

  17. Ink-jet printed colorimetric gas sensors on plastic foil

    NASA Astrophysics Data System (ADS)

    Courbat, Jerome; Briand, Danick; de Rooij, Nico F.

    2010-08-01

    An all polymeric colorimetric gas sensor with its associated electronics for ammonia (NH3) detection targeting low-cost and low-power applications is presented. The gas sensitive layer was inkjet printed on a plastic foil. The use of the foil directly as optical waveguide simplified the fabrication, made the device more cost effective and compatible with large scale fabrication techniques, such as roll to roll processes. Concentrations of 500 ppb of NH3 in nitrogen with 50% of RH were measured with a power consumption of about 868 μW in an optical pulsed mode of operation. Such sensors foresee applications in the field of wireless systems, for environmental and safety monitoring. The fabrication of the planar sensor was based on low temperature processing. The waveguide was made of PEN or PET foil and covered with an ammonia sensitive layer deposited by inkjet printing, which offered a proper and localized deposition of the film. The influence of the substrate temperature and its surface pretreatment were investigated to achieve the optimum deposition parameters for the printed fluid. To improve the light coupling from the light source (LED) to the detectors (photodiodes), polymeric micro-mirrors were patterned in an epoxy resin. With the printing of the colorimetric film and additive patterning of polymeric micro-mirrors on plastic foil, a major step was achieved towards the implementation of full plastic selective gas sensors. The combination with printed OLED and PPD would further lead to an integrated all polymeric optical transducer on plastic foil fully compatible with printed electronics processes.

  18. Improvements in Fabrication of Elastic Scattering Foils Used to Measure Neutron Yield by the Magnetic Recoil Spectrometer

    DOE PAGESBeta

    Reynolds, H. G.; Schoff, M. E.; Farrell, M. P.; Gatu Johnson, M.; Bionta, R. M.; Frenje, J. A.

    2016-08-01

    The magnetic recoil spectrometer uses a deuterated polyethylene polymer (CD2) foil to measure neutron yield in inertial confinement fusion experiments. Higher neutron yields in recent experiments have resulted in primary signal saturation in the detector CR-39 foils, necessitating the fabrication of thinner CD2 foils than established methods could provide. A novel method of fabricating deuterated polymer foils is described. The resulting foils are thinner, smoother, and more uniform in thickness than the foils produced by previous methods. Here, these new foils have successfully been deployed at the National Ignition Facility, enabling higher neutron yield measurements than previous foils, with nomore » primary signal saturation.« less

  19. Terahertz radiation generation by nonlinear mixing of two laser beams over a thin foil

    NASA Astrophysics Data System (ADS)

    Chauhan, Santosh; Parashar, J.

    2015-07-01

    Terahertz radiation generation via nonlinear mixing of two laser beams incident over a thin metal foil is explored. The lasers exert a ponderomotive force on the electrons of metal foil at beat frequency which lies in the terahertz range. The metal foil acts as antenna, producing terahertz radiations, highly directional in nature.

  20. Terahertz radiation generation by nonlinear mixing of two laser beams over a thin foil

    SciTech Connect

    Chauhan, Santosh; Parashar, J.

    2015-07-31

    Terahertz radiation generation via nonlinear mixing of two laser beams incident over a thin metal foil is explored. The lasers exert a ponderomotive force on the electrons of metal foil at beat frequency which lies in the terahertz range. The metal foil acts as antenna, producing terahertz radiations, highly directional in nature.

  1. Development of the carbon foils as charge strippers for high-intensity uranium ion beams

    NASA Astrophysics Data System (ADS)

    Hasebe, Hiroo; Kuboki, Hironori; Okuno, Hiroki; Fukunishi, Nobuhisa; Kamigaito, Osamu; Imao, Hiroshi; Goto, Akira; Kase, Masayuki

    2011-11-01

    carbon foil (C-foil) is commonly used as a charge stripper in the heavy-ion accelerators. Since 2005, the polymer-coated carbon foils (PCC-foils) have been fabricated at Nishina Center to prepare larger and thicker C-foils than those previously used as charge strippers. However, the multi-layer PCC-foils did not have sufficiently long life-time. Since August 2009, a new magnetron sputtering system is used to fabricate a thick C-foil. The foils coated with polymer are used as strippers. Life-times of the new single-layer PCC-foils under the uranium beam were measured in two configurations: at the first one a small piece of C-foil was attached to a fixed holder and in the second one a large C-foil was attached to a "rotating-cylinder stripper" device. The properties of the new single-layer PCC-foils and the results of the life-time measurements are reported in this contribution.

  2. Intracranial malignant triton tumor in a patient with neurofibromatosis type 1: case report and review of the literature.

    PubMed

    Smith, Ross E; Kebriaei, Meysam A; Gard, Andrew P; McComb, Rodney D; Bridge, Julia A; Lennarson, Peter J

    2014-04-01

    We report the fourth case of an intracranial malignant triton tumor not associated with a cranial nerve in a 26-year-old male with a clinical history of neurofibromatosis type 1. The patient was found unresponsive and displayed confusion, lethargy, hyperreflexia, and dysconjugate eye movements upon arrival at the emergency room. MRI revealed a large bifrontal mass. Biopsy demonstrated a high-grade spindle cell tumor with focal areas of rhabdomyoblasts that stained positive for desmin, myogenin, and muscle-specific actin. Electron microscopy showed skeletal muscle differentiation. Based on the clinical history of NF1 and the pathologic results, a diagnosis of malignant triton tumor was made. The differential diagnosis, immunohistochemistry, molecular genetics, and treatment of malignant triton tumor are reviewed. PMID:23633163

  3. Triton Emission Spectra in Some Target Nuclei Irradiated by Ultra-Fast Neutrons

    NASA Astrophysics Data System (ADS)

    Tel, E.; Kaplan, A.; Aydın, A.; Büyükuslu, H.; Demirkol, İ.; Arasoğlu, A.

    2010-08-01

    High-current proton accelerator technologies make use of spallation neutrons produced in ( p,xn) and ( n,xn) nuclear reactions on high-Z targets. The produced neutrons are moderated by heavy water. These moderated neutrons are subsequently captured on 3He to produce tritium via the ( n,p) reaction. Tritium self-sufficiency must be maintained for a commercial power plant. So, working out the systematics of ( n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, triton emission spectra by using ultra-fast neutrons (incident neutron energy >50 MeV), the ( n,xt) reactions for some target nuclei as 16O, 27Al, 56Fe, 59Co, 208Pb and 209Bi have been investigated. In the calculations, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.

  4. SCALE Continuous-Energy Monte Carlo Depletion with Parallel KENO in TRITON

    SciTech Connect

    Goluoglu, Sedat; Bekar, Kursat B; Wiarda, Dorothea

    2012-01-01

    The TRITON sequence of the SCALE code system is a powerful and robust tool for performing multigroup (MG) reactor physics analysis using either the 2-D deterministic solver NEWT or the 3-D Monte Carlo transport code KENO. However, as with all MG codes, the accuracy of the results depends on the accuracy of the MG cross sections that are generated and/or used. While SCALE resonance self-shielding modules provide rigorous resonance self-shielding, they are based on 1-D models and therefore 2-D or 3-D effects such as heterogeneity of the lattice structures may render final MG cross sections inaccurate. Another potential drawback to MG Monte Carlo depletion is the need to perform resonance self-shielding calculations at each depletion step for each fuel segment that is being depleted. The CPU time and memory required for self-shielding calculations can often eclipse the resources needed for the Monte Carlo transport. This summary presents the results of the new continuous-energy (CE) calculation mode in TRITON. With the new capability, accurate reactor physics analyses can be performed for all types of systems using the SCALE Monte Carlo code KENO as the CE transport solver. In addition, transport calculations can be performed in parallel mode on multiple processors.

  5. The Infrared Optical Constants of Ethane and Ethylene Ices: Relevance to Pluto and Triton

    NASA Astrophysics Data System (ADS)

    Gerakines, Perry A.; Hudson, Reggie L.; Moore, Marla H.

    2014-11-01

    As New Horizons approaches the Pluto system, our research group is carrying out new infrared optical-constants measurements of hydrocarbons with an emphasis on temperatures below ~70 K. Our goal is to add to the relatively meager literature on this subject and to provide electronic versions of state-of-the-art data, since the abundances of such molecules cannot be deduced without accurate optical constants (n, k) and reference spectra. Ethane (C2H6) and ethylene (C2H4) are the subject of the present work. Photochemical models of the atmospheres of Pluto and Triton predict both of these molecules as abundant precipitating products (Krasnopolsky and Cruikshank, 1995, JGR 100, 21271-21286; Krasnopolsky and Cruikshank,1999, JGR 104, 21979-21996), and the infrared reflectance features of both Pluto and Triton are well fit by laboratory spectra when pure, solid ethane is included as a component (Cruikshank et al., 2006, Bulletin of the AAS 38, 518). Here we present our recent measurements of near- and mid-infrared optical constants for ethane and ethylene in multiple ice phases and at multiple temperatures. We also report new measurements of the index of refraction of each ice at 670 nm. Comparisons are made to earlier work where possible. Electronic versions of our new results are available at http://science.gsfc.nasa.gov/691/cosmicice/constants.html.

  6. Scrambled self-assembly of bacteriochlorophylls c and e in aqueous Triton X-100 micelles.

    PubMed

    Saga, Yoshitaka; Saiki, Tatsuya; Takahashi, Naoya; Shibata, Yutaka; Tamiaki, Hitoshi

    2014-01-01

    Bacteriochlorophyll (BChl) e was coassembled with BChl c in Triton X-100 micelles in aqueous solutions. The Qy absorption bands of the coaggregates were positioned between those of aggregates consisting solely of BChl c or e. The electronic absorption spectra of the coaggregates could not be reproduced by linear combinations of the spectra of the aggregates consisting solely of each pigment, but they were in line with the simulated spectra for the self-aggregates in which both BChls were randomly distributed. These suggest that BChls c and e are not spatially separated; they are homogenously distributed over the self-aggregates to give electronic spectra that are different from those of the aggregate consisting solely of each pigment. Deaggregation of the scrambled self-aggregates by excess Triton X-100 did not produce any spectral components assigned to an aggregate consisting solely of either BChl c or e. Acid-induced decomposition of the scrambled aggregates showed different kinetics from those of the aggregates consisting solely of each pigment. These also support the homogeneous distribution of BChls c and e in the scrambled self-aggregates. These results will be useful to investigate the major light-harvesting antenna systems of green photosynthetic bacteria that contain two kinds of chlorosomal BChls. PMID:24308290

  7. Bioavailability of hydrocarbons to bacterial consortia during Triton X-100 mediated biodegradation in aqueous media.

    PubMed

    Pęziak, Daria; Piotrowska, Aleksandra; Marecik, Roman; Lisiecki, Piotr; Woźniak, Marta; Szulc, Alicja; Ławniczak, Łukasz; Chrzanowski, Łukasz

    2013-01-01

    The aim of our study was to investigate the effect of Triton X-100 on the biodegradation efficiency of hexadecane and phenanthrene carried out by two bacterial consortia. It was established that the tested consortia were not able to directly uptake compounds closed in micelles. It was observed that in micellar systems the nonionic synthetic surfactant was preferentially degraded (the degradation efficiency of Triton X-100 after 21 days was 70% of the initial concentration - 500 mg/l), followed by a lesser decomposition of hydrocarbon released from the micelles (30% for hexadecane and 20% for phenanthrene). However, when hydrocarbons were used as the sole carbon source, 70% of hexadecane and 30% of phenanthrene were degraded. The degradation of the surfactant did not contribute to notable shifts in bacterial community dynamics, as determined by Real-Time PCR. The obtained results suggest that if surfactant-supplementation is to be used as an integral part of a bioremediation process, then possible bioavailability decrease due to entrapment of the contaminant into surfactant micelles should also be taken into consideration, as this phenomenon may have a negative impact on the biodegradation efficiency. Surfactant-induced mobilization of otherwise recalcitrant hydrocarbons may contribute to the spreading of contaminants in the environment and prevent their biodegradation. PMID:24432333

  8. Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate

    PubMed Central

    2011-01-01

    Background In order to develop colloidal drug carriers with desired properties, it is important to determine physico-chemical characteristics of these systems. Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic (sodium lauryl ether sulfate) surfactant having oxyethylene groups in the polar head and following bile salts: cholate, deoxycholate and 7-oxodeoxycholate. Results The micellization behaviour of binary anionic-nonionic and anionic-anionic surfactant mixtures was investigated by conductivity and surface tension measurements. The results of the study have been analyzed using Clint's, Rubingh's, and Motomura's theories for mixed binary systems. The negative values of the interaction parameter indicate synergism between micelle building units. It was noticed that Triton X-100 and sodium lauryl ether sulfate generate the weakest synergistic interactions with sodium deoxycholate, while 7-oxodeoxycholate creates the strongest attractive interaction with investigated co-surfactants. Conclusion It was concluded that increased synergistic interactions can be attributed to the larger number of hydrophilic groups at α side of the bile salts. Additionally, 7-oxo group of 7-oxodeoxycholate enhance attractive interactions with selected co-surfactants more than 7-hydroxyl group of sodium cholate. PMID:22206681

  9. Comparison of fluence-to-dose conversion coefficients for deuterons, tritons and helions.

    PubMed

    Copeland, Kyle; Friedberg, Wallace; Sato, Tatsuhiko; Niita, Koji

    2012-02-01

    Secondary radiation in aircraft and spacecraft includes deuterons, tritons and helions. Two sets of fluence-to-effective dose conversion coefficients for isotropic exposure to these particles were compared: one used the particle and heavy ion transport code system (PHITS) radiation transport code coupled with the International Commission on Radiological Protection (ICRP) reference phantoms (PHITS-ICRP) and the other the Monte Carlo N-Particle eXtended (MCNPX) radiation transport code coupled with modified BodyBuilder™ phantoms (MCNPX-BB). Also, two sets of fluence-to-effective dose equivalent conversion coefficients calculated using the PHITS-ICRP combination were compared: one used quality factors based on linear energy transfer; the other used quality factors based on lineal energy (y). Finally, PHITS-ICRP effective dose coefficients were compared with PHITS-ICRP effective dose equivalent coefficients. The PHITS-ICRP and MCNPX-BB effective dose coefficients were similar, except at high energies, where MCNPX-BB coefficients were higher. For helions, at most energies effective dose coefficients were much greater than effective dose equivalent coefficients. For deuterons and tritons, coefficients were similar when their radiation weighting factor was set to 2. PMID:21474471

  10. Dual scattering foil design for poly-energetic electron beams.

    PubMed

    Kainz, K K; Antolak, J A; Almond, P R; Bloch, C D; Hogstrom, K R

    2005-03-01

    The laser wakefield acceleration (LWFA) mechanism can accelerate electrons to energies within the 6-20 MeV range desired for therapy application. However, the energy spectrum of LWFA-generated electrons is broad, on the order of tens of MeV. Using existing laser technology, the therapeutic beam might require a significant energy spread to achieve clinically acceptable dose rates. The purpose of this work was to test the assumption that a scattering foil system designed for a mono-energetic beam would be suitable for a poly-energetic beam with a significant energy spread. Dual scattering foil systems were designed for mono-energetic beams using an existing analytical formalism based on Gaussian multiple-Coulomb scattering theory. The design criterion was to create a flat beam that would be suitable for fields up to 25 x 25 cm2 at 100 cm from the primary scattering foil. Radial planar fluence profiles for poly-energetic beams with energy spreads ranging from 0.5 MeV to 6.5 MeV were calculated using two methods: (a) analytically by summing beam profiles for a range of mono-energetic beams through the scattering foil system, and (b) by Monte Carlo using the EGS/BEAM code. The analytic calculations facilitated fine adjustments to the foil design, and the Monte Carlo calculations enabled us to verify the results of the analytic calculation and to determine the phase-space characteristics of the broadened beam. Results showed that the flatness of the scattered beam is fairly insensitive to the width of the input energy spectrum. Also, results showed that dose calculated by the analytical and Monte Carlo methods agreed very well in the central portion of the beam. Outside the useable field area, the differences between the analytical and Monte Carlo results were small but significant, possibly due to the small angle approximation. However, these did not affect the conclusion that a scattering foil system designed for a mono-energetic beam will be suitable for a poly

  11. The absorption coefficient of the liquid N2 2.15-micron band and application to Triton

    NASA Technical Reports Server (NTRS)

    Grundy, William M.; Fink, Uwe

    1991-01-01

    The present measurements of the temperature dependence exhibited by the liquid N2 2.15-micron 2-0 collision-induced band's absorption coefficient and integrated absorption show the latter to be smaller than that of the N2 gas, and to decrease with decreasing temperature. Extrapolating this behavior to Triton's nominal surface temperature yields a new estimate of the N2-ice grain size on the Triton south polar cap; a mean N2 grain size of 0.7-3.0 cm is consistent with grain growth rate calculation results.

  12. Thermal effects on the clearance and stiffness of foil journal bearings for a Brayton cycle turboalternator

    NASA Technical Reports Server (NTRS)

    Eshel, A.

    1972-01-01

    An analysis of foil journal bearings for a NASA Brayton Cycle Unit (BRU) is presented. The study represents an extension of previous work in that it includes the effects of thermal expansion of foil-bearing components, as well as an improved model of the influence of foil flexure. The results presented give the bearing film thickness, the bearing stiffness, and the foil tension as functions of the operating temperatures and the elasto-hydrodynamic and geometrical parameters pertinent to the design of BRU foil bearings. A computer program for the evaluation of design data and for parametric studies is included.

  13. Physical vapor deposited aluminum foils from high energy density physics experiments

    SciTech Connect

    Barthell, B.L.; Anderson, W.E.; Gomez, V.M.; Henneke, B.F.; Moore, J.E.; Reeves, G.A.; Salazar, M.A.; Townsend, J.D.

    1995-09-01

    Fabrication of cylindrical aluminum load foils and graded thickness aluminum vacuum opening switch foils is described. Load foils are vaporized by joule heating and imploded by J {times} B forces to stagnate on axis and create soft x-rays. Plasma flow switch foils are mounted to shunt the vacuum power flow channel of a coaxial gun and are vaporized by joule heating. The resultant graded density plasma is magnetically driven down the annular power flow channel. Opening switch action occurs when the shunt plasma crosses a load slot in the center conductor. These foil components have been used in both the Pegasus and Procyon experiments.

  14. Quasi-static analysis of foil journal bearings for a Brayton cycle turboalternator

    NASA Technical Reports Server (NTRS)

    Eshel, A.

    1974-01-01

    A quasi-static analysis is presented for foil journal bearings designed for a NASA Brayton Cycle Turboalternator. Included in the analysis are effects of 'slack' (due to flexural rigidity of the foil), of frictionally restrained extension of the foil-length in contact with cylindrical guides, of fluid inertia and compressibility, and of thermal expansion of rotor, foil and supporting structure. Comparisons are made with results of early experiments performed by Licht (1968, 1969) and recent data of Licht and Branger (1973). Variatons of film thickness, foil tension and bearing stiffness are presented graphically as functions of pertinent parameters for the case of operation in zero-gravity environment.

  15. Development of carbon foils with a thickness of up to 600 μg/cm 2

    NASA Astrophysics Data System (ADS)

    Kindler, Birgit; Hartmann, Willi; Hübner, Annett; Lommel, Bettina; Steiner, Jutta

    2010-02-01

    Carbon foils are applied as stripper for the heavy-ion accelerator as well as targets in different experiments at GSI. Carbon foils in a thickness range 5-100 μg/cm 2 are routinely produced with good homogeneity and excellent durability. Foils thicker than 100 μg/cm 2 used to be purchased. To overcome problems that emerged and intensified in some applications we started to advance our own carbon production towards higher thickness. We describe the production of carbon foils up to a thickness of 600 μg/cm 2, report on first tests as stripper foils and as targets, and discuss our future plans.

  16. Triton College 1999 NCA Self-Study Report. Prepared for the North Central Association of Colleges and Schools Commission on Institutions of Higher Education.

    ERIC Educational Resources Information Center

    Triton Coll., River Grove, IL.

    The primary purpose of this report is to demonstrate that Triton College meets the North Central Association's (NCA's) twenty-four General Institutional Requirements and satisfies NCA's five criteria of Educational Excellence. To achieve this goal, the report presents a comprehensive picture of Triton College's mission, organization, programs, and…

  17. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOEpatents

    Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

    1996-01-01

    A method of welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads.

  18. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOEpatents

    Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

    1996-03-19

    A method is described for welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads. 7 figs.

  19. Lifetime dependence of nitrided carbon stripper foils on sputter angle during N+ ion beam sputtering

    NASA Astrophysics Data System (ADS)

    Sugai, I.; Oyaizu, M.; Takeda, Y.; Kawakami, H.; Kawasaki, K.; Hattori, T.; Kadono, T.

    2015-09-01

    We fabricated high-lifetime thin nitride carbon stripper (NCS) foils with high nitrogen contents using ion-beam sputtering with reactive nitrogen gas and investigated the dependence of their lifetimes on the sputter angle. The nitrogen in carbon foils plays a critical role in determining their lifetime. Therefore, in order to investigate the effects of the nitrogen level in NCS foils on foil lifetime, we measured the sputtering yield for different sputter angles at a sputtering voltage of 10 kV while using carbon-based targets. We also measured the nitrogen-to-carbon thickness ratios of the foils using Rutherford backscattering spectrometry. The foils made at a sputter angle of 15° using a glassy amorphous carbon target exhibited an average increase of 200-fold in lifetime when compared to commercially available foils.

  20. Non-uniformity effects of the inter-foil distance on GEM detector performance

    NASA Astrophysics Data System (ADS)

    Yan, Huang; Han, YI; Zhi-Gang, Xiao; Zhao, Zhang; Wen-Jing, Cheng; Li-Ming, Lü; Wei-Hua, Yan; Ren-Sheng, Wang; Hong-Jie, Li; Yan, Zhang; Li-Min, Duan; Rong-Jiang, Hu; Chen-Gui, Lu; He-Run, Yang; Peng, Ma; Hai-Yan, Gao

    2016-04-01

    The non-uniformity effect of the inter-foil distance has been studied using a gaseous electron multiplication (GEM) detector with sensitive area of 50mm × 50mm. A gradient of the inter-foil distance is introduced by using spacers with different heights at the two ends of the foil gap. While the cluster size and the intrinsic spatial resolution show insignificant dependence on the inter-foil distance, the gain exhibits an approximately linear dependence on the inter-foil distance. From the slope, a quantitative relationship between the change of the inter-foil distance and the change of the gain is derived, which can be used as a method to evaluate the non-uniformity of the foil gap in the application of large-area GEM detectors. Supported by National Natural Science Foundation of China (11375094, U1332207, 11120101004), and by Tsinghua University Initiative Scientific Research Program

  1. Temperature Measurements at Material Interfaces with Thin-Foil Gauges

    NASA Astrophysics Data System (ADS)

    Morley, Mike J.; Chapman, David J.; Proud, William G.

    2009-12-01

    Measurements of shock heating are important in determining Equations of State that incorporate entropic effects. The use of thin-foil nickel gauges to measure shock heating in material was proposed by Rosenberg et al. in the 1980s. This research investigates the use of such commercial thin-foil gauges at interfaces between materials of different thermal and shock properties. The technique requires analysis of the resistance changes of the gauge which is a function of both temperature and stress. The response of manganin gauges to shock loading is well understood, and was used to calibrate for the piezoresistive effect in nickel. Results are presented for a variety of well-characterised materials and the applicability of the proposed method discussed.

  2. Temperature measurements at material interfaces with thin-foil gauges

    NASA Astrophysics Data System (ADS)

    Morley, Mike; Chapman, David; Proud, William

    2009-06-01

    Measurements of shock heating are important in determining Equations of State that incorporate entropic effects. The use of thin-foil nickel gauges to measure shock heating in material was proposed by Rosenberg et al. in the 1980s. This research investigates the use of such commercial thin-foil gauges at interfaces between materials of different thermal and shock properties. The technique requires analysis of the resistance changes of the gauge which is a function of both temperature and stress. The response of manganin gauges to shock loading is well understood, and was used to calibrate for the piezoresistive effect in nickel. Results are presented for a variety of well-characterised materials and the applicability of the proposed method discussed.

  3. Underlying principle of efficient propulsion in flexible plunging foils

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-Jue; He, Guo-Wei; Zhang, Xing

    2014-12-01

    Passive flexibility was found to enhance propulsive efficiency in swimming animals. In this study, we numerically investigate the roles of structural resonance and hydrodynamic wake resonance in optimizing efficiency of a flexible plunging foil. The results indicates that (1) optimal efficiency is not necessarily achieved when the driving frequency matches the structural eigenfrequency; (2) optimal efficiency always occurs when the driving frequency matches the wake resonant frequency of the time averaged velocity profile. Thus, the underlying principle of efficient propulsion in flexible plunging foil is the hydrodynamic wake resonance, rather than the structural resonance. In addition, we also found that whether the efficiency can be optimized at the structural resonant point depends on the strength of the leading edge vortex relative to that of the trailing edge vortex. The result of this work provides new insights into the role of passive flexibility in flapping-based propulsion.

  4. Electrostatic adhesion of polymer particles to a foil electrode

    NASA Astrophysics Data System (ADS)

    Ziteng, Li; Praeger, Matthew; Smallwood, Jeremy; Lewin, Paul

    2015-10-01

    The SPABRINK EU project requires temporary adhesion of coloured solid “ink” particles to a surface, for later recovery and reuse. This is achieved through the use of dielectrophoretic force under the control of a voltage applied to an interdigitated electrode pattern on the polymer foil. One concern is the ability to hold particles under vibration conditions. In this paper we present an experimental study of the adhesion of 50-300 μm polymer particles to an experimental interdigitated electrode structure on flexible polymer foil. Powder loss as a function of calibrated displacement and applied voltage to the electrodes are presented. This is compared with theoretical results obtained by modelling adhesion using Pohl's equation in terms of an “adhesion factor”. Some difficulties in directly comparing experimental and modelling results are discussed.

  5. Gas Foil Bearing Technology Advancements for Closed Brayton Cycle Turbines

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; Bruckner, Robert J.; DellaCorte, Christopher; Radil, Kevin C.

    2007-01-01

    Closed Brayton Cycle (CBC) turbine systems are under consideration for future space electric power generation. CBC turbines convert thermal energy from a nuclear reactor, or other heat source, to electrical power using a closed-loop cycle. The operating fluid in the closed-loop is commonly a high pressure inert gas mixture that cannot tolerate contamination. One source of potential contamination in a system such as this is the lubricant used in the turbomachine bearings. Gas Foil Bearings (GFB) represent a bearing technology that eliminates the possibility of contamination by using the working fluid as the lubricant. Thus, foil bearings are well suited to application in space power CBC turbine systems. NASA Glenn Research Center is actively researching GFB technology for use in these CBC power turbines. A power loss model has been developed, and the effects of a very high ambient pressure, start-up torque, and misalignment, have been observed and are reported here.

  6. CHARACTERIZATION OF MONOLITHIC FUEL FOIL PROPERTIES AND BOND STRENGTH

    SciTech Connect

    D E Burkes; D D Keiser; D M Wachs; J S Larson; M D Chapple

    2007-03-01

    Understanding fuel foil mechanical properties, and fuel / cladding bond quality and strength in monolithic plates is an important area of investigation and quantification. Specifically, what constitutes an acceptable monolithic fuel – cladding bond, how are the properties of the bond measured and determined, and what is the impact of fabrication process or change in parameters on the level of bonding? Currently, non-bond areas are quantified employing ultrasonic determinations that are challenging to interpret and understand in terms of irradiation impact. Thus, determining mechanical properties of the fuel foil and what constitutes fuel / cladding non-bonds is essential to successful qualification of monolithic fuel plates. Capabilities and tests related to determination of these properties have been implemented at the INL and are discussed, along with preliminary results.

  7. Direct drive foil implosion experiments on Pegasus II

    SciTech Connect

    Cochrane, J.C.; Bartsch, R.R.; Benage, J.F.; Forman, P.R.; Gribble, R.F.; Hockaday, M.Y.P.; Hockaday, R.G.; Ladish, J.S.; Oona, H.; Parker, J.V.; Shlachter, J.S.; Wysocki, F.J.

    1993-05-01

    Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos Above Ground Experiments (AGEX) program. The goal of the program is to produce an intense (>100 TW) source of soft x-rays from the thermalization of the KE of a 1 to 10 MJ collapsing plasma source. The radiation pulse should have a maximum duration of several tens of nanoseconds and will be used in the study of fusion conditions and material properties. This paper addresses z-pinch experiments done on a capacitor bank where the radiating plasma source is formed by an imploding annular aluminum foil driven by the J {times} B forces generated by the current flowing through the foil.

  8. Plasma flow switch and foil implosion experiments on Pegasus II

    SciTech Connect

    Cochrane, J.C.; Bartsch, R.R.; Benage, J.R.; Forman, P.R.; Gribble, R.F.; Ladish, J.S.; Oona, H.; Parker, J.V.; Scudder, D.W.; Shlachter, J.S.; Wysocki, F.J.

    1993-01-01

    Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos AGEX (Above Ground EXperiments) program. A goal of the program is to produce an intense (> 100 TW) source of soft x-rays from the thermalization of the kinetic energy of a 1 to 10 MJ plasma implosion. The radiation pulse should have a maximum duration of several 10's of nanoseconds and will be used in the study of fusion conditions and material properties. The radiating plasma source will be generated by the thermalization of the kinetic energy of an imploding cylindrical, thin, metallic foil. This paper addresses experiments done on a capacitor bank to develop a switch (plasma flow switch) to switch the bank current into the load at peak current. This allows efficient coupling of bank energy into foil kinetic energy.

  9. Plasma flow switch and foil implosion experiments on Pegasus II

    SciTech Connect

    Cochrane, J.C.; Bartsch, R.R.; Benage, J.R.; Forman, P.R.; Gribble, R.F.; Ladish, J.S.; Oona, H.; Parker, J.V.; Scudder, D.W.; Shlachter, J.S.; Wysocki, F.J.

    1993-07-01

    Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos AGEX (Above Ground EXperiments) program. A goal of the program is to produce an intense (> 100 TW) source of soft x-rays from the thermalization of the kinetic energy of a 1 to 10 MJ plasma implosion. The radiation pulse should have a maximum duration of several 10`s of nanoseconds and will be used in the study of fusion conditions and material properties. The radiating plasma source will be generated by the thermalization of the kinetic energy of an imploding cylindrical, thin, metallic foil. This paper addresses experiments done on a capacitor bank to develop a switch (plasma flow switch) to switch the bank current into the load at peak current. This allows efficient coupling of bank energy into foil kinetic energy.

  10. Fabrication of microcoined metal foil Rayleigh-Taylor targets

    NASA Astrophysics Data System (ADS)

    Randall, Greg; Vecchio, James; Fitzsimmons, Paul; Knipping, Jack; Wall, Don; Vu, Matthew; Giraldez, Emilio; Remington, Tane; Blue, Brent; Farrell, Michael; Nikroo, Abbas

    2013-03-01

    Rippled metal foils are currently sought for high strain rate material strength studies. For example, the growth of these ripples by the Rayleigh-Taylor instability after a laser-induced ramped compression yields strength behavior at extremely high strain rate. Because metals of interest (iron, tantalum, steel, etc.) typically cannot be diamond turned, we employ a microcoining process to imprint the ~ 5 μm deep by ~ 50 μm long ripples into the metal surface. The process consists of nitriding a steel die, diamond turning the die, and then pressing the die into a polished metal foil of choice (Seugling et al., Proc EUSPEN Int. Conference, 2010). This work details recent process developments, characterization techniques, and important physics for fabrication of these rippled metal targets.

  11. Energy loss of 132Xe-ions in thin foils

    NASA Astrophysics Data System (ADS)

    Trzaska, W. H.; Knyazheva, G. N.; Perkowski, J.; Andrzejewski, J.; Khlebnikov, S. V.; Kozulin, E. M.; Lyapin, V. G.; Malkiewicz, T.; Mutterer, M.

    2009-10-01

    The energy loss of 132Xe-ions in C, Al, Ni, Ag, Lu, Au, Pb and Th foils was measured in the energy range from 0.1 to 5 MeV/u using the TOF-E method. The results are compared with previously published data and with the predictions of several computer codes. They include theoretical codes: PASS, CASP, semi-empirical programs: SRIM, LET and the Hubert table predictions.

  12. Nickel foil microcantilevers for magnetic manipulation and localized heating

    PubMed Central

    Gaitas, Angelo; McNaughton, Brandon H.

    2014-01-01

    Cellular manipulation has been investigated by a number of techniques. In this manuscript nickel foil microcantilevers were used for magnetophoresis and manipulation of microparticles and magnetically labeled HeLa cells. The cantilevers were also used for localized heating in liquid, reaching biologically relevant temperatures. This work aims to develop cantilevers for sample enrichment, manipulation, and thermal applications, offering an inexpensive and versatile solution compatible with standard tools in research and clinical diagnostic testing, such as microwell plates. PMID:25541581

  13. The investigation of electrolytic surface roughening for PCB copper foil

    NASA Astrophysics Data System (ADS)

    Lee, Shuo-Jen; Liu, Chao-Kai

    2013-10-01

    This study is the application of the principle of electrochemical. The anodic dissolution has no concentration polarization. Hence, electrolyte life is substantially increased. The waste copper is high in ion concentration with a recovery value. As compared with the current PCB chemical pre-treatment method, it may have advantages of cost-saving, improvement of overall efficiency, reduction of production costs and reduction of the amount of waste generated. In the development of the copper foil for electrochemical roughening process, the use of electrolysis reaction affects the copper surface dissolution to form a unique bump coarsening. It will increase in the surface area of the copper foil to improve dry film solder mask and the adhesion between the copper surfaces. Four electrolytes, two neutral salts and two acids, were selected to explore the best of the electrolytic roughening parameters of temperature, time and voltage. The surface roughness and the surface morphology of the copper foil were measured before and after the electrolytic surface roughening. Finally, after repeated experiments, electrolytes A and B copper generates obvious inter-granular corrosion, resulting in a rough surface similar to the chemical pre-treatment. On the other hands, the surface morphology resulted from electrolytes C and D appears more like pitting. Both electrolytic could generate surface roughness of Ra 0.3 um roughened copper surface higher than industrial standard.

  14. Thin-foil reflection gratings for Constellation-X

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Akilian, Mireille; Chang, Chih-Hao; Forest, Craig R.; Joo, Chulmin; Lapsa, Andrew; Montoya, Juan C.; Schattenburg, Mark L.

    2004-10-01

    The Reflection Grating Spectrometer (RGS) on Constellation-X is designed to supply astronomers with high spectral resolution in the soft x-ray band from 0.25 to 2 keV. High resolution, large collecting area and low mass at grazing incidence require very flat and thin grating substrates, or thin-foil optics. Thin foils typically have a diameter-to-thickness ratio of 200 or higher and as a result very low stiffness. This poses a number of technological challenges in the areas of shaping, handling, positioning, and mounting of such optics. The most minute forces (gravity sag, friction, thermal mismatch with optic mount, etc.) can lead to intolerable deformations and limit figure metrology repeatability. We present results of our efforts in the manipulation and metrology of suitable grating substrates, utilizing a novel low-stress foil holder with friction-reducing flexures. A large number of reflection gratings is needed to achieve the required collecting area. We have employed nanoimprint lithography (NIL) - which uses imprint films as thin as 100 nm or less - for the high-fidelity and low-stress replication from 100 mm diameter saw-tooth grating masters.

  15. Structure and mechanical properties of foils made of nanocrystalline beryllium

    NASA Astrophysics Data System (ADS)

    Zhigalina, O. M.; Semenov, A. A.; Zabrodin, A. V.; Khmelenin, D. N.; Brylev, D. A.; Lizunov, A. V.; Nebera, A. L.; Morozov, I. A.; Anikin, A. S.; Orekhov, A. S.; Kuskova, A. N.; Mishin, V. V.; Seryogin, A. V.

    2016-07-01

    The phase composition and structural features of (45-90)-μm-thick foils obtained from nanocrystalline beryllium during multistep thermomechanical treatment have been established using electron microscopy, electron diffraction, electron backscattering diffraction, and energy-dispersive analysis. This treatment is shown to lead to the formation of a structure with micrometer- and submicrometer-sized grains. The minimum average size of beryllium grains is 352 nm. The inclusions of beryllium oxide (BeO) of different modifications with tetragonal (sp. gr. P42/ mnm) and hexagonal (sp. gr. P63/ mmc) lattices are partly ground during deformation to a size smaller than 100 nm and are located along beryllium grain boundaries in their volume, significantly hindering migration during treatment. The revealed structural features of foils with submicrometer-sized crystallites provide the thermal stability of their structural state. Beryllium with this structure is a promising material for X-ray instrument engineering and for the production of ultrathin (less than 10 μm) vacuum-dense foils with very high physicomechanical characteristics.

  16. Fission foil detector calibrations with high energy protons

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Frank, A. L.

    1995-01-01

    Fission foil detectors (FFD's) are passive devices composed of heavy metal foils in contact with muscovite mica films. The heavy metal nuclei have significant cross sections for fission when irradiated with neutrons and protons. Each isotope is characterized by threshold energies for the fission reactions and particular energy-dependent cross sections. In the FFD's, fission fragments produced by the reactions are emitted from the foils and create latent particle tracks in the adjacent mica films. When the films are processed surface tracks are formed which can be optically counted. The track densities are indications of the fluences and spectra of neutrons and/or protons. In the past, detection efficiencies have been calculated using the low energy neutron calibrated dosimeters and published fission cross sections for neutrons and protons. The problem is that the addition of a large kinetic energy to the (n,nucleus) or (p,nucleus) reaction could increase the energies and ranges of emitted fission fragments and increase the detector sensitivity as compared with lower energy neutron calibrations. High energy calibrations are the only method of resolving the uncertainties in detector efficiencies. At high energies, either proton or neutron calibrations are sufficient since the cross section data show that the proton and neutron fission cross sections are approximately equal. High energy proton beams have been utilized (1.8 and 4.9 GeV, 80 and 140 MeV) for measuring the tracks of fission fragments emitted backward and forward.

  17. Material Parameters for Creep Rupture of Austenitic Stainless Steel Foils

    NASA Astrophysics Data System (ADS)

    Osman, H.; Borhana, A.; Tamin, M. N.

    2014-08-01

    Creep rupture properties of austenitic stainless steel foil, 347SS, used in compact recuperators have been evaluated at 700 °C in the stress range of 54-221 MPa to establish the baseline behavior for its extended use. Creep curves of the foil show that the primary creep stage is brief and creep life is dominated by tertiary creep deformation with rupture lives in the range of 10-2000 h. Results are compared with properties of bulk specimens tested at 98 and 162 MPa. Thin foil 347SS specimens were found to have higher creep rates and higher rupture ductility than their bulk specimen counterparts. Power law relationship was obtained between the minimum creep rate and the applied stress with stress exponent value, n = 5.7. The value of the stress exponent is indicative of the rate-controlling deformation mechanism associated with dislocation creep. Nucleation of voids mainly occurred at second-phase particles (chromium-rich M23C6 carbides) that are present in the metal matrix by decohesion of the particle-matrix interface. The improvement in strength is attributed to the precipitation of fine niobium carbides in the matrix that act as obstacles to the movement of dislocations.

  18. Low-energy multiple-Coulomb scattering in thick foils

    SciTech Connect

    Morrill, S.M.

    1984-01-01

    Angular and energy distributions were taken using proton and ..cap alpha..-particle beams of energies 2 to 10 MeV incident on a variety of thick foils. Foils were chosen from commonly used materials and to span the periodic table. Foil thicknesses were chosen which resulted in approximately 20-60% energy losses. The lower-energy experiments were done using the Brigham Young University 4-MeV Van de Graaff accelerator while the higher-energy experiments were performed using the Triangle Universities Nuclear Laboratory (TUNL) tandem Van de Graaff. Angular distributions are characterized by the angles at which the distribution had dropped to the 1/e, 1/10, and 1/100 points of their initial values. Energy distributions are characterized by the mean energy and the width of the energy-straggling distribution of the emerging particle. Comparisons are made to the appropriate theories including the angular distribution theory of Nigam, Sundaresan, and Wu (NSW), and the straggling theory of Bethe. Improvements to the NSW method by using an effective energy and effective nuclear charge are discussed.

  19. Low-Energy Multiple-Coulomb Scattering in Thick Foils.

    NASA Astrophysics Data System (ADS)

    Morrill, Steven M.

    Angular and energy distributions were taken using proton and alpha-particle beams of energies 2--10 MeV incident on a variety of thick foils. Foils were chosen from commonly used materials and to span the periodic table. Foil thicknesses were chosen which resulted in approximately 20--60% energy losses. The lower-energy experiments were done using the Brigham Young University 4-MeV Van de Graaff accelerator while the higher-energy experiments were performed using the Triangle Universities Nuclear Laboratory (TUNL) tandem Van de Graaff. Angular distributions were characterized by the angles at which the distribution had dropped to the 1/e, 1/10, and 1/100 points of their initial values. Energy distributions were characterized by the mean energy and the width of the energy straggling distribution of the emerging particle. Comparisons were made to the appropriate theories including the angular distribution theory of Nigam, Sundaresan, and Wu (NSW), and the straggling theory of Bethe. Improvements to the NSW method by using an effective energy and effective nuclear charge were discussed.

  20. Production of large screen-mounted aluminium neutralizer foils

    NASA Astrophysics Data System (ADS)

    Stoner, John O.

    1989-10-01

    In order to convert large-diameter beams of H - to neutral H atoms, aluminum foils having a diameter of 90 cm or more and an areal density of typically 8-12 μg/cm 2 have been proposed. Production of such foils, uniform in thickness to ±20% or better and mounted on thin wire grids, has been accomplished by careful control of substrate preparation, parting-agent application, spatial location of coating filaments, floating speed and temperature, and pickup procedure. Lexan (TM) polycarbonate substrates have been used, because of their uniformity of surface quality. Evaporated NaCl has been used as the parting agent, and an alloy containing 1% silicon rather than pure aluminum has been used as the foil material for greater strength and reliability. To obtain coated areas sufficiently large and uniform, substrates having dimensions of 1.2 m × 1.2 m have been used. A specially configured water tank having a volume of 3.2 m 3 has been built to accept such large substrates. Floating has been done in chilled water to improve its stability, minimize variations in surface tension, and to prevent the development of air bubbles on immersed surfaces. Fractional coverage of better than 95% on meshes having unsupported diameters of greater than 90 cm can now be obtained on a routine basis.

  1. Flow energy harvesting -- another application of the biomimetic flapping foils

    NASA Astrophysics Data System (ADS)

    Zhu, Qiang; Peng, Zhangli

    2009-11-01

    Imitating fish fins and insect wings, flapping foils are usually used for biomimetic propulsion. Theoretical studies and experiments have demonstrated that through specific combinations of heaving and pitching motions, these foils can also extract energy from incoming wind or current. Compared with conventional flow energy harvesting devices based upon rotating turbines, this novel design promises mitigated impact upon the environment. To achieve the required motions, existing studies focus on hydrodynamic mode coupling, in which a periodic pitching motion is activated and a heaving motion is then generated by the oscillating lifting force. Energy extraction is achieved through a damper in the heaving direction (representing the generator). This design involves a complicated control and activation system. In addition, there is always the possibility that the energy required to activate the system exceeds the energy recovered by the generator. We have discovered that a much simpler device without activation, a 2DOF foil mounted on a rotational spring and a damper undergoing flow-induced motions can achieve stable flow energy harvesting. Using Navier-Stokes simulations we predicted different behaviors of the system during flow-induced vibrations and identified the specific requirements to achieve controllable periodic motions essential for stable energy harvesting. The energy harvesting capacity and efficiency were also determined.

  2. Comparison of EXAFS Foil Spectra from Around the World

    SciTech Connect

    Kelly, S. D.; Bare, S. R.; Greenlay, N.; Azevedo, G.; Balasubramanian, M.; Barton, D.; Chattopadhyay, S.; Fakra, S.; Johannessen, B.; Newville, M.; Pena, J.; Pokrovski, G. S; Proux, O.; Priolkar, K.; Ravel, B.; Webb, S. M.

    2010-07-16

    The EXAFS spectra of Cu and Pd foil from many different beamlines and synchrotrons are compared to address the dependence of the amplitude reduction factor (S{sub 0}{sup 2}) on beamline specific parameters. Even though S{sub 0}{sup 2} is the same parameter as the EXAFS coordination number, the value for S{sub 0}{sup 2} is given little attention, and is often unreported. The S{sub 0}{sup 2} often differs for the same material due to beamline and sample attributes, such that no importance is given to S{sub 0}{sup 2}-values within a general range of 0.7 to 1.1. EXAFS beamlines have evolved such that it should now be feasible to use standard S{sub 0}{sup 2} values for all EXAFS measurements of a specific elemental environment. This would allow for the determination of the imaginary energy (Ei) to account for broadening of the EXAFS signal rather than folding these errors into an effective S{sub 0}{sup 2}-value. To test this concept, we model 11 Cu-foil and 6 Pd-foil EXAFS spectra from around the world to compare the difference in S{sub 0}{sup 2}- and Ei-values.

  3. Grain structure of thin electrodeposited and rolled copper foils

    SciTech Connect

    Merchant, H.D. . E-mail: HarishMerchant@aol.com; Liu, W.C.; Giannuzzi, L.A.; Morris, J.G.

    2004-12-15

    Planar and cross-section light optical and transmission electron microscopy (TEM) and X-ray diffraction analysis have been used to characterize the technologically relevant thin copper films and foils. The grain structure and grain orientation of (i) 1-15 {mu}m deposit on the polyimide (PI) substrate (ii) 5-35 {mu}m free-standing foil and (iii) 200 {mu}m sheet prepared by the industrial scale rolling or electrodeposit process have been examined. It is shown that the rolled foil structure is highly anisotropic due to grain stretching during rolling; the pancaked grains circumscribe a dislocation cell substructure. Thermal exposure in the 423-453 K range results in full anneal softening, while initiating the polygonization of cellular substructure, the formation of new large grains by discontinuous recrystallization and the transformation of the near <111> deformation textures into the near <100> anneal textures. The texture transformation is facilitated when the oxygen content of copper is reduced from the normal 100-400 ppm level or when a low level silver ({approx}200 ppm) addition is made to copper. Depending upon the electrodeposition conditions or the nature of additives introduced in the electrolyte, it is possible to develop an electrodeposit with (a) a truly equiaxed, fine, twin-free, randomly oriented grain structure or (b) a relatively coarse grain structure, accompanied by extensive twinning, z (growth)-direction grain extension, columnar grain morphology and strong <220> crystallographic texture. Between (a) and (b), it is possible to tailor the processing to obtain a mix of fine and coarse grains, a large fraction of random orientation component (weak near <220> textures), moderate twinning, and vestiges of columnar grain morphology and z-direction grain extension. The anneal softening is not accompanied by significant grain structure modification or by texture change; somewhat above the softening temperature, an in situ grain growth ensues. For both

  4. ENVIRONMENTAL TECHNOLOGY VERIFICATION: JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT: TRITON SYSTEMS, LLC SOLID BOWL CENTRIFUGE, MODEL TS-5000

    EPA Science Inventory

    Verification testing of the Triton Systems, LLC Solid Bowl Centrifuge Model TS-5000 (TS-5000) was conducted at the Lake Wheeler Road Field Laboratory Swine Educational Unit in Raleigh, North Carolina. The TS-5000 was 48" in diameter and 30" deep, with a bowl capacity of 16 ft3. ...

  5. A 3D general circulation model for Pluto and Triton with fixed volatile abundance and simplified surface forcing

    NASA Astrophysics Data System (ADS)

    Zalucha, Angela M.; Michaels, Timothy I.

    2013-04-01

    We present a 3D general circulation model of Pluto and Triton's atmospheres, which uses radiative-conductive-convective forcing. In both the Pluto and Triton models, an easterly (prograde) jet is present at the equator with a maximum magnitude of 10-12 m s-1 and 4 m s-1, respectively. Neither atmosphere shows any significant overturning circulation in the meridional and vertical directions. Rather, it is horizontal motions (mean circulation and transient waves) that transport heat meridionally at a magnitude of 1 and 3 × 107 W at Pluto's autumn equinox and winter solstice, respectively (seasons referenced to the Northern Hemisphere). The meridional and dayside-nightside temperature contrast is small (⩽5 K). We find that the lack of vertical motion can be explained on Pluto by the strong temperature inversion in the lower atmosphere. The height of the Voyager 2 plumes on Triton can be explained by the dynamical properties of the lower atmosphere alone (i.e., strong wind shear) and does not require a thermally defined troposphere (i.e., temperature decreasing with height at the surface underlying a region of temperature increasing with height). The model results are compared with Pluto stellar occultation light curve data from 1988, 2002, 2006, and 2007 and Triton light curve data from 1997.

  6. Crude soybean hull peroxidase treatment of phenol in synthetic and real wastewater: enzyme economy enhanced by Triton X-100.

    PubMed

    Steevensz, Aaron; Madur, Sneha; Feng, Wei; Taylor, Keith E; Bewtra, Jatinder K; Biswas, Nihar

    2014-02-01

    Soybean peroxidase (SBP)-catalyzed removal of phenol from wastewater has been demonstrated as a feasible wastewater treatment strategy and a non-ionic surfactant, Triton X-100, has the potential for increasing the enzyme economy of the process. Systematic studies on the enzyme-surfactant system have been lacking as well as demonstration of its applicability to industrial wastewater. This paper addresses those two gaps, the latter based on real wastewater from alkyd resin manufacture. The minimum effective Triton X-100 concentrations for crude SBP-catalyzed phenol conversion (≥95%) over 1-10 mM showed a linear trend. To illustrate translation of such lab results to real-world samples, this data were used to optimize crude SBP needed for phenol conversion over that concentration range. Triton X-100 increases enzyme economy by 10- to 13-fold. This treatment protocol was directly applied to tote-scale (700-1000 L) treatment of alkyd resin wastewater, with phenol ranging from 7 to 28 mM and total organic carbon content of >40 g/L, using a crude SBP extract derived from dry soybean hulls by simple aqueous elution. This extract can be used to remove phenol from a complex industrial wastewater and the process is markedly more efficient in the presence of Triton X-100. The water is thus rendered amenable to conventional biological treatment whilst the hulls could still be used in feed, thus adding further value to the crop. PMID:24411447

  7. Measurements of confined alphas and tritons in the MHD quiescent core of TFTR plasmas using the pellet charge exchange diagnostic

    SciTech Connect

    Medley, S.S.; Budny, R.V.; Mansfield, D.K.

    1996-05-01

    The energy distributions and radial density profiles of the fast confined trapped alpha particles in DT experiments on TFTR are being measured in the energy range 0.5--3.5 MeV using a Pellet Charge eXchange (PCX) diagnostic. A brief description of the measurement technique which involves active neutral particle analysis using the ablation cloud surrounding an injected impurity pellet as the neutralizer is presented. This paper focuses on alpha and triton measurements in the core of MHD quiescent TFTR discharges where the expected classical slowing down and pitch angle scattering effects are not complicated by stochastic ripple diffusion and sawtooth activity. In particular, the first measurement of the alpha slowing down distribution up to the birth energy, obtained using boron pellet injection, is presented. The measurements are compared with predictions using either the TRANSP Monte-Carlo code and/or a Fokker-Planck Post-TRANSP processor code, which assumes that the alphas and tritons are well confined and slow down classically. Both the shape of the measured alpha and triton energy distributions and their density ratios are in good agreement with the code calculations. The authors conclude that the PCX measurements are consistent with classical thermalization of the fusion-generated alphas and tritons.

  8. SECULAR EVOLUTION OF A SATELLITE BY TIDAL EFFECT: APPLICATION TO TRITON

    SciTech Connect

    Correia, Alexandre C. M.

    2009-10-10

    Some of the satellites in the solar system, including the Moon, appear to have been captured from heliocentric orbits at some point in their past, and then have evolved to the present configurations. The exact process of how this trapping occurred is unknown, but the dissociation of a planetesimal binary in the gravitational field of the planet, gas drag, or a massive collision seem to be the best candidates. However, all these mechanisms leave the satellites in elliptical orbits that need to be damped to the present almost circular ones. Here, we give a complete description of the secular tidal evolution of a satellite just after entering a bounding state with the planet. In particular, we take into account the spin evolution of the satellite, which has often been assumed synchronous in previous studies. We apply our model to Triton and successfully explain some geophysical properties of this satellite, as well as the main dynamical features observed for the Neptunian system.

  9. 3D calculation of Tucson-Melbourne 3NF effect in triton binding energy

    SciTech Connect

    Hadizadeh, M. R.; Tomio, L.; Bayegan, S.

    2010-08-04

    As an application of the new realistic three-dimensional (3D) formalism reported recently for three-nucleon (3N) bound states, an attempt is made to study the effect of three-nucleon forces (3NFs) in triton binding energy in a non partial wave (PW) approach. The spin-isospin dependent 3N Faddeev integral equations with the inclusion of 3NFs, which are formulated as function of vector Jacobi momenta, specifically the magnitudes of the momenta and the angle between them, are solved with Bonn-B and Tucson-Melbourne NN and 3N forces in operator forms which can be incorporated in our 3D formalism. The comparison with numerical results in both, novel 3D and standard PW schemes, shows that non PW calculations avoid the very involved angular momentum algebra occurring for the permutations and transformations and it is more efficient and less cumbersome for considering the 3NF.

  10. The electric dipole moment of rhodopsin solubilized in Triton X-100.

    PubMed Central

    Petersen, D C; Cone, R A

    1975-01-01

    The electric dipole moment of solubilized rhodopsin was determined with dielectric dispersion measurements. Rhodopsin was extracted from disc membranes of cattle rod outer segments with the nonionic detergent Triton X-100. The dipole moment of rhodopsin at its isoionic point in the detergent micelle is 720 D (150 charge-A). This value is comparable to dipole moments of nonmembrane proteins, especially those which tend to aggregate or polymerize. Flash irradiation of the rhodopsin results in an increase in the dipole moment of about 25 D (5 charge-A). The light-induced increase in dipole moment appears to be composed of two parts--a faster component related to a change in the number of protons bound by rhodopsin and a slower component apparently independent of the change in proton binding. PMID:1203446

  11. Polypyrrole nanoparticles fabricated via Triton X-100 micelles template approach and their acetone gas sensing property

    NASA Astrophysics Data System (ADS)

    Li, Fake; Li, Hang; Jiang, Hongmin; Zhang, Kejun; Chang, Kai; Jia, Shuangrong; Jiang, Wenbin; Shang, Ya; Lu, Weiping; Deng, Shaoli; Chen, Ming

    2013-09-01

    Nano-scaled polypyrrole (PPy) particles have been successfully synthesized with the help of Triton X-100 micelles via soft template approach. The polypyrrole nanoparticles have been spin-coated on surface acoustic wave (SAW) transducers to demonstrate their sensing capability toward acetone gas exposure. Field Emission Scanning Electron Microscopes (FE-SEM) and Fourier transform infrared (FT-IR) spectroscopy have been utilized to characterize these PPy nanoparticles. The PPy nanoparticles have an average diameter of 95 nm. The responses of the sensors are linearly associated with the acetone concentrations in the range from 5.5 ppm to 80 ppm. In response to 5.5 ppm acetone exposure, the response and recovery time are 9 s and 8.3 s, respectively. SAW sensors coated with PPy nanoparticles were potentially useful to detect acetone.

  12. Microstructure and Mechanical Properties of AA1235 Aluminum Foil Stocks Produced Directly from Electrolytic Aluminum Melt

    NASA Astrophysics Data System (ADS)

    Xiong, Hanqing; Yu, Kun; Wen, Li; Yao, Sujuan; Dai, Yilong; Wang, Zhifeng

    2016-02-01

    A new process is developed to obtain high-quality AA1235 aluminum foil stocks and to replace the traditional manufacture process. During the new manufacture process, AA1235 aluminum sheets are twin-roll casted directly through electrolytic aluminum melt (EAM), and subsequently the sheets are processed into aluminum foil stocks by cold rolling and annealing. Microstructure and mechanical properties of the AA1235 aluminum sheets produced through such new process are investigated in each state by optimal microscope, scanning electron microscopy, X-ray diffraction, orientation imaging microscopy, transmission electron microscopy, etc. The results show that compared with the traditional AA1235 aluminum foil stocks produced through re-melted aluminum melt (RAM), the amount of impurities is decreased in the EAM aluminum foil stocks. The EAM aluminum foil stock obtains less β-FeSiAl5 phases, but more α-Fe2SiAl8 phases. The elongation of EAM aluminum foil stocks is improved significantly owing to more cubic orientation. Especially, the elongation value of the EAM aluminum foil stocks is approximately 25 pct higher than that of the RAM aluminum foil stocks. As a result, the EAM aluminum foil stocks are at an advantage in increasing the processing performance for the aluminum foils during subsequent processes.

  13. Improved in vitro assay for determining the mucin adherence of bacteria sensitive to Triton X-100 treatment.

    PubMed

    Tsilia, Varvara; Van den Abbeele, Pieter; Van de Wiele, Tom

    2015-09-01

    Mucin-associated microbiota are in relatively close contact with the intestinal epithelium and may thus have a more pronounced effect on host health. We have previously developed a simple mucin agar assay to simulate initial mucus colonization by intestinal microbial communities. Adherence of microbiota was estimated using flow cytometry after detachment with Triton X-100. In this study, the effect of this detergent on the cultivability of both virulent and commensal strains was investigated. Mucin attachment of selected strains was evaluated using the mucin adhesion assay. Bacteria were dislodged from the mucin surface by incubation with Triton or from the whole mucin agar layer using a stomacher. Mechanical extraction resulted in 1.24 ± 0.42, 2.69 ± 0.44, and 1.56 ± 0.85 log CFU/mL higher plate counts of Lactobacillus rhamnosus, Bacillus cereus, and Escherichia coli strains, respectively, than the chemical method. The sensitivity of bacteria to Triton varied among microbial species and strains. Among others, Triton inhibited the growth of Salmonella enterica LMG 10396 and Pseudomonas aeruginosa LMG 8029 on laboratory media, although these bacteria maintained their viability during this treatment. Only Gram-positive strains, Enterococcus hirae LMG 6399 and L. rhamnosus GG, were not affected by this detergent. Therefore, the mechanical method is recommended for the extraction of mucin-adhered bacteria that are sensitive to Triton, especially when followed by traditional cultivation techniques. However, this approach can also be recommended for strains that are not affected by this detergent, because it resulted in higher recovery of adhered L. rhamnosus GG compared to the chemical extraction. PMID:25702162

  14. Pu-Zr alloy for high-temperature foil-type fuel

    DOEpatents

    McCuaig, Franklin D.

    1977-01-01

    A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron reflux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.

  15. Pu-ZR Alloy high-temperature activation-measurement foil

    DOEpatents

    McCuaig, Franklin D.

    1977-08-02

    A nuclear reactor fuel alloy consists essentially of from slightly greater than 7 to about 4 w/o zirconium, balance plutonium, and is characterized in that the alloy is castable and is rollable to thin foils. A preferred embodiment of about 7 w/o zirconium, balance plutonium, has a melting point substantially above the melting point of plutonium, is rollable to foils as thin as 0.0005 inch thick, and is compatible with cladding material when repeatedly cycled to temperatures above 650.degree. C. Neutron flux densities across a reactor core can be determined with a high-temperature activation-measurement foil which consists of a fuel alloy foil core sandwiched and sealed between two cladding material jackets, the fuel alloy foil core being a 7 w/o zirconium, plutonium foil which is from 0.005 to 0.0005 inch thick.

  16. Beam Loss due to Foil Scattering in the SNS Accumulator Ring

    SciTech Connect

    Holmes, Jeffrey A; Plum, Michael A

    2012-01-01

    In order to better understand the contribution of scattering from the primary stripper foil to losses in the SNS ring, we have carried out calculations using the ORBIT Code aimed at evaluating these losses. These calculations indicate that the probability of beam loss within one turn following a foil hit is ~1.8 10-8 , where is the foil thickness in g/cm2, assuming a carbon foil. Thus, for a typical SNS stripper foil of thickness = 390 g/cm2, the probability of loss within one turn of a foil hit is ~7.0 10-6. This note describes the calculations used to arrive at this result, presents the distribution of these losses around the SNS ring, and compares the calculated results with observed ring losses for a well-tuned production beam.

  17. Measurement of the radon diffusion through a nylon foil for different air humidities

    SciTech Connect

    Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

    2015-08-17

    The dependency of the radon penetration through a nylon foil on air humidity was measured. Such information is needed for the tracking part of the SuperNEMO detector, which is planned to be shielded against radon by nylon foil and in which the air humidity is not negligible. The long term measurements of radon penetration through nylon foils for different air humidities were performed with the radon diffusion setup constructed at the IEAP, CTU in Prague. The setup consists of two stainless steel hemispheres with Si detector in each of them. Both hemispheres are separated by the tested foil. While the left hemisphere contains high Rn activity, the right part contains only activity caused by the radon penetration through the tested foil. Obtained results of this study with a nylon foil with the thickness of 50 µm are presented.

  18. Measurement of the radon diffusion through a nylon foil for different air humidities

    NASA Astrophysics Data System (ADS)

    Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

    2015-08-01

    The dependency of the radon penetration through a nylon foil on air humidity was measured. Such information is needed for the tracking part of the SuperNEMO detector, which is planned to be shielded against radon by nylon foil and in which the air humidity is not negligible. The long term measurements of radon penetration through nylon foils for different air humidities were performed with the radon diffusion setup constructed at the IEAP, CTU in Prague. The setup consists of two stainless steel hemispheres with Si detector in each of them. Both hemispheres are separated by the tested foil. While the left hemisphere contains high Rn activity, the right part contains only activity caused by the radon penetration through the tested foil. Obtained results of this study with a nylon foil with the thickness of 50 µm are presented.

  19. Analysis of cartilage-polydioxanone foil composite grafts.

    PubMed

    Kim, James H; Wong, Brian

    2013-12-01

    This study presents an analytical investigation into the mechanical behavior of a cartilage-polydioxanone (PDS) plate composite grafts. Numerical methods are used to provide a first-order, numerical model of the flexural stiffness of a cartilage-PDS graft. Flexural stiffness is a measure of resistance to bending and is inversely related to the amount of deformation a structure may experience when subjected to bending forces. The cartilage-PDS graft was modeled as a single composite beam. Using Bernoulli-Euler beam theory, a closed form equation for the theoretical flexural stiffness of the composite graft was developed. A parametric analysis was performed to see how the flexural properties of the composite model changed with varying thicknesses of PDS foil. The stiffness of the cartilage-PDS composite using 0.15-mm-thick PDS was four times higher than cartilage alone. The composite with a 0.5-mm-thick PDS graft was only 1.7 times stiffer than the composite with the 0.15-mm-thick PDS graft. Although a thicker graft material will yield higher flexural stiffness for the composite, the relationship between composite stiffness and PDS thickness is nonlinear. After a critical point, increments in graft thickness produce gradually smaller improvements in flexural stiffness. The small increase in stiffness when using the thicker PDS foils versus the 0.15 mm PDS foil may not be worth the potential complications (prolonged foreign body reaction, reduction in nutrient diffusion to cartilage) of using thicker artificial grafts. PMID:24327249

  20. Experimental research of the fine foil explosion dynamics

    NASA Astrophysics Data System (ADS)

    Zhigalin, A. S.; Rousskikh, A. G.; Oreshkin, V. I.; Chaikovsky, S. A.; Ratakhin, N. A.; Kuznetsov, V. V.

    2014-11-01

    The work is devoted to studying of substances properties at high specific deposit energy using double-frame pulsed backlighting system. The high specific deposit energy was reached at electrical conductor explosion (ECE). Fast mode of ECE was investigated. Fine foils of aluminum, cooper, titanium and nickel were used as conductors. Experiments were carried out on the experimental complex consisting of three current generators. The first generator WEG-' was used for explosion of the fine conductors. This generator represents fast capacitor with capacity 250 nF, which was charged to voltage 10 to 30 kV. The investigated conductor was mounted in special holder and the foil contacts with the electrodes were soldered. Two other generators - radiographs XPG-1 and G2 with x-pinch load were used two frame X-ray backlighting imaging. The generators current pulses had amplitude 300 kA and rising time 180 ns with a low inductance load. Four crossed molybdenum wires with diameter of 25 μm were used to form an x-pinch. Using of the x-pinches soft x-ray radiation the images of exploded foil were registered with temporal resolution of 2 ns. The images were detected by a photo film located behind the filter. The x-ray imaging, together with the measurements of the current flowing through a conductor and voltage on the exploded conductor had allowed inferring of the energy deposited into the conductor, delay time of the bubbles formation relative to the moment of current- cutoff and the time dependence of the vapor bubbles quantity.

  1. Short-pulse high intensity laser thin foil interaction

    NASA Astrophysics Data System (ADS)

    Audebert, Patrick

    2003-10-01

    The technology of ultrashort pulse laser generation has progressed to the point that optical pulses larger than 10 J, 300 fs duration or shorter are routinely produced. Such pulses can be focused to intensities exceeding 10^18 W/cm^2. With high contrast pulses, these focused intensities can be used to heat solid matter to high temperatures with minimal hydrodynamic expansion, producing an extremely high energy-density state of matter for a short period of time. This high density, high temperature plasma can be studied by x-ray spectroscopy. We have performed experiments on thin foils of different elements under well controlled conditions at the 100 Terawatt laser at LULI to study the characteristics X-ray emission of laser heated solids. To suppress the ASE effect, the laser was frequency doubled. S-polarized light with a peak intensity of 10^19W/cm^2 was used to minimize resonance absorption. To decrease the effect of longitudinal temperature gradients very thin (800 μ) aluminum foil targets were used. We have also studied the effect of radial gradient by limiting the measured x-ray emission zone using 50μ or 100μ pinhole on target. The spectra, in the range 7-8Å, were recorded using a conical crystal spectrometer coupled to a 800 fs resolution streak camera. A Fourier Domain Interferometry (FDI) of the back of the foil was also performed providing a measurement of the hydrodynamic expansion as function of time for each shot. To simulate the experiment, we used the 1D hydrodynamic code FILM with a given set of plasma parameter (ρ, Te) as initial conditions. The X-ray emission was calculated by post processing hydrodynamic results with a collisional-radiative model which uses super-configuration average atomic data. The simulation reproduces the main features of the experimental time resolved spectrum.

  2. Reactive multilayer synthesis of hard ceramic foils and films

    DOEpatents

    Makowiecki, D.M.; Holt, J.B.

    1996-02-13

    A method is disclosed for synthesizing hard ceramic materials such as carbides, borides and aluminides, particularly in the form of coatings provided on another material so as to improve the wear and abrasion performance of machine tools, for example. The method involves the sputter deposition of alternating layers of reactive metals with layers of carbon, boron, or aluminum and the subsequent reaction of the multilayered structure to produce a dense crystalline ceramic. The material can be coated on a substrate or formed as a foil which can be coiled as a tape for later use.

  3. Reactive multilayer synthesis of hard ceramic foils and films

    DOEpatents

    Makowiecki, Daniel M.; Holt, Joseph B.

    1996-01-01

    A method for synthesizing hard ceramic materials such as carbides, borides nd aluminides, particularly in the form of coatings provided on another material so as to improve the wear and abrasion performance of machine tools, for example. The method involves the sputter deposition of alternating layers of reactive metals with layers of carbon, boron, or aluminum and the subsequent reaction of the multilayered structure to produce a dense crystalline ceramic. The material can be coated on a substrate or formed as a foil which can be coild as a tape for later use.

  4. Synthetic Graphene Grown by Chemical Vapor Deposition on Copper Foils

    NASA Astrophysics Data System (ADS)

    Chung, Ting Fung; Shen, Tian; Cao, Helin; Jauregui, Luis A.; Wu, Wei; Yu, Qingkai; Newell, David; Chen, Yong P.

    2013-04-01

    The discovery of graphene, a single layer of covalently bonded carbon atoms, has attracted intense interest. Initial studies using mechanically exfoliated graphene unveiled its remarkable electronic, mechanical and thermal properties. There has been a growing need and rapid development in large-area deposition of graphene film and its applications. Chemical vapor deposition on copper has emerged as one of the most promising methods in obtaining large-scale graphene films with quality comparable to exfoliated graphene. In this paper, we review the synthesis and characterizations of graphene grown on copper foil substrates by atmospheric pressure chemical vapor deposition. We also discuss potential applications of such large-scale synthetic graphene.

  5. Laser Proton acceleration from mass limited silicon foils

    NASA Astrophysics Data System (ADS)

    Zeil, K.; Kraft, S.; Richter, T.; Metzkes, J.; Bussmann, M.; Schramm, U.; Sauerbrey, R.; Cowan, T. E.; Fuchs, J.; Buffechoux, S.

    2009-11-01

    We present recent studies on laser proton acceleration experiments using mass limited silicon targets. Small micro machined silicon foils with 2 μm thickness and 20x20 μm2 to 100x100μm2 size mounted on very tiny stalks were shot with the 100 TW LULI Laser (long pulse 150 fs) and with the new 150 TW DRACO Laser facility (short pulse 30 fs) of the Research Centre Dresden-Rossendorf. The experiments were carried out using high contrast levels. Proton spectra have been measured with magnetic spectrometers and radio chromic film stacks.

  6. Promising HE for explosive welding of thin metallic foils

    NASA Astrophysics Data System (ADS)

    Deribas, A. A.; Mikhaylov, A. L.; Titova, N. N.; Zocher, Marvin A.

    2012-03-01

    Experimental results are presented on the development of a high explosive (HE) suitable for the welding of thin metallic foils. The explosive is formed from a mixture of brisant HE (RDX or PETN) and an inert material, namely sodium bicarbonate. Sodium bicarbonate releases a rather large quantity of gas during decomposition, the effects of which are discussed. Measurements of detonation velocity and critical thickness for specific mixture combinations are presented. It is shown that particle size (of the RDX or PETN component) has a significant effect upon detonation velocity and critical thickness. Compositions were developed which have a stable detonation velocity ~2 km/s with a layer thickness ~ 2 mm.

  7. Prediction of Gas Lubricated Foil Journal Bearing Performance

    NASA Technical Reports Server (NTRS)

    Carpino, Marc; Talmage, Gita

    2003-01-01

    This report summarizes the progress in the first eight months of the project. The objectives of this research project are to theoretically predict the steady operating conditions and the rotor dynamic coefficients of gas foil journal bearings. The project is currently on or ahead of schedule with the development of a finite element code that predicts steady bearing performance characteristics such as film thickness, pressure, load, and drag. Graphical results for a typical bearing are presented in the report. Project plans for the next year are discussed.

  8. Standardizable method for testing foil-substrate adherence

    NASA Astrophysics Data System (ADS)

    Schell, Karel J.; Klinker, Han; van Renesse, Rudolf L.

    2002-04-01

    An increasing number of currencies is provided with an Optically Variable Device (OVD) as a counterfeit deterrent. The device is adhered to the substrate by a hot melt adhesive. Adherence is generally tested with an adhesive tape, a practical test that sufficed up to now. Nevertheless, the question may be raised if a method can be developed with a better discriminating power as well as a larger potential for standardization. A feasibility test with the IGT printability tester, using a high viscosity pick up oil, shows promising results. This paper presents the testing method, shows a few preliminary results and discusses these results with respect to the foil application method.

  9. Optical observations of molecular dissociation in thin foils

    SciTech Connect

    Berry, H.G.; Gay, T.J.; Brooks, R.L.

    1981-01-01

    We have measured the intensity and polarizations of light emitted from atomic excited states of dissociated molecular ions. Using HeH/sup +/ projectiles, we have observed factors of 1 to 5 enhancements of the light from n=3, /sup 1/ /sup 3/P,D states of He I and some He II and H I emissions. Observations of Lyman-..cap alpha.. emission after dissociation of H/sub 2//sup +/ and H/sub 3//sup +/ show rapid variations in light yield for small internuclear separations at the foil surface.

  10. Reactive multilayer synthesis of hard ceramic foils and films

    SciTech Connect

    Makowiecki, D.M.; Holt, J.B.

    1993-12-31

    Disclosed is method for synthesizing hard ceramic materials such as carbides, borides and aluminides, particularly in the form of coatings provided on another material so as to improve the wear and abrasion performance of machine tools, for example. Method involves the sputter deposition of alternating layers of reactive metals with layers of carbon, boron, or aluminum and the subsequent reaction of the multilayered structure to produce a dense crystalline ceramic. The material can be coated on a substrate or formed as a foil which can be coiled as a tape for later use.

  11. [Investigation on the spectral characteristics and existing state of a substituted 3H-indole molecular probe in triton X-100 reverse micelle].

    PubMed

    Luo, Jun-jian; Li, Jian; Shen, Xing-hai; Gao, Hong-cheng

    2005-02-01

    The interactions between a fluorescent molecular probe, i. e., [2-(p-hexylamino) phenyl-3, 3-dimethyl-5-ethoxycarbonyl-3H-indole] methyldioctadecylammonium iodide (A) and Triton X-100/heptane/hexanol/water reverse micelle have been investigated by spectroscopy. Micropolarity of the environment, fluorescence anisotropy parameter and the pH effect of A in Triton X-100 reverse micelle were determined. Furthermore, the state of water in reverse micellar systems was studied by FTIR. According to the above experimental results, some information on the structure of Triton X-100 reverse micelle was obtained and the probable site of A in this system was discussed. PMID:15852849

  12. Comparison of carbon stripper foils under operational conditions at the Los Alamos proton storage ring

    SciTech Connect

    Spickerman, Thomas; Borden, Michael J; Macek, Robert J; Sugai, Isao

    2008-01-01

    At the 39{sup th} ICFA Advanced Beam Dynamics Workshop HB 2006 and the 23{sup rd} INTDS World Conference we reported on first results of a test of nanocrystalline diamond foils developed at ORNL under operational conditions at the Los Alamos Proton Storage Ring (PSR). We have continued these tests during the 2006 and 2007 run cycles and have been able to compare the diamond foils with the foils that are normally in use in PSR, which were originally developed by Sugai at KEK. We have gathered valuable information regarding foil lifetime, foil related beam losses and electron emission at the foil. Additional insight was gained under unusual beam conditions where the foiIs are subjected to higher temperatures. In the 2007 run cycle we also tested a Diamond-like-Carbon foil developed at TRIUMF. A Hybrid-Boron-Carbon foil, also developed by Sugai, is presently in use with the PSR production beam. We will summarize our experience with these different foil types.

  13. Role of induced vortex interaction in a semi-active flapping foil based energy harvester

    NASA Astrophysics Data System (ADS)

    Wu, J.; Chen, Y. L.; Zhao, N.

    2015-09-01

    The role of induced vortex interaction in a semi-active flapping foil based energy harvester is numerically examined in this work. A NACA0015 airfoil, which acts as an energy harvester, is placed in a two-dimensional laminar flow. It performs an imposed pitching motion that subsequently leads to a plunging motion. Two auxiliary smaller foils, which rotate about their centers, are arranged above and below the flapping foil, respectively. As a consequence, the vortex interaction between the flapping foil and the rotating foil is induced. At a Reynolds number of 1100 and the position of the pitching axis at one-third chord, the effects of the distance between two auxiliary foils, the phase difference between the rotating motion and the pitching motion as well as the frequency of pitching motion on the power extraction performance are systematically investigated. It is found that compared to the single flapping foil, the efficiency improvement of overall power extraction for the flapping foil with two auxiliary foils can be achieved. Based on the numerical analysis, it is indicated that the enhanced power extraction, which is caused by the increased lift force, thanks to the induced vortex interaction, directly benefits the efficiency enhancement.

  14. Design and validation of novel scattering foils for modulated electron radiation therapy.

    PubMed

    Connell, T; Seuntjens, J

    2014-05-21

    Modulated Electron Radiation Therapy (MERT) continues to be an area of interest to various groups, however, the scattering foils used in beam flattening have not been optimized for this modality. In this work, the feasibility of novel scattering foils specifically designed for MERT is investigated using Monte Carlo methods. Different designs based on foil material, shape and thickness were analyzed. It was shown that low atomic number materials such as aluminum were optimal, while shaped foils such as those employed in current dual foil designs were not necessary. Aluminum foil thickness between 0.36 mm and 1.50 mm were capable of sufficiently broadening beams with energies between 12 MeV and 20 MeV respectively, with beams of lower energies receiving sufficient scatter from the treatment head components and air scatter. Finally, custom foils were manufactured based upon previously simulated designs and were placed into the beamline of a 2100 EX accelerator, and showed excellent agreement between the simulated and measured PDDs and profiles. Custom foils achieved higher dose rates on the central axis compared to the clinical foils by factors of 5.4, 4.9 and 4.5 for 12 MeV, 16 MeV and 20 MeV, respectively. PMID:24743426

  15. Hydrodynamics of foils swimming in a side-by-side configuration

    NASA Astrophysics Data System (ADS)

    Dewey, Peter; Moored, Keith; Quinn, Daniel; Smits, Alexander

    2013-11-01

    Experimental and computational results are presented on a pair of hydrofoils undergoing pitch oscillations in a side-by-side configuration. The time-averaged forces and propulsive efficiency are independently measured for each foil for a range of separation distances and oscillation phase differentials between the two foils. The results are compared to an isolated foil to determine if the presence of a second foil can yield an improvement to the propulsive characteristics of the system. While the exact performance of the side-by-side foils is strongly dependent on the separation distance and phase differential between the foils, it is found that under certain configurations an enhancement in net thrust is achieved by the presence of a second foil. The wake patterns shed by the foils as they oscillate are also examined and compared to the propulsive characteristics. A series of four stable wake configurations are observed that depend on the phase differential between the foils. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI grant number N00014-08-1-0642.

  16. Goal-directed mechanisms that constrain retrieval predict subsequent memory for new "foil" information.

    PubMed

    Vogelsang, David A; Bonnici, Heidi M; Bergström, Zara M; Ranganath, Charan; Simons, Jon S

    2016-08-01

    To remember a previous event, it is often helpful to use goal-directed control processes to constrain what comes to mind during retrieval. Behavioral studies have demonstrated that incidental learning of new "foil" words in a recognition test is superior if the participant is trying to remember studied items that were semantically encoded compared to items that were non-semantically encoded. Here, we applied subsequent memory analysis to fMRI data to understand the neural mechanisms underlying the "foil effect". Participants encoded information during deep semantic and shallow non-semantic tasks and were tested in a subsequent blocked memory task to examine how orienting retrieval towards different types of information influences the incidental encoding of new words presented as foils during the memory test phase. To assess memory for foils, participants performed a further surprise old/new recognition test involving foil words that were encountered during the previous memory test blocks as well as completely new words. Subsequent memory effects, distinguishing successful versus unsuccessful incidental encoding of foils, were observed in regions that included the left inferior frontal gyrus and posterior parietal cortex. The left inferior frontal gyrus exhibited disproportionately larger subsequent memory effects for semantic than non-semantic foils, and significant overlap in activity during semantic, but not non-semantic, initial encoding and foil encoding. The results suggest that orienting retrieval towards different types of foils involves re-implementing the neurocognitive processes that were involved during initial encoding. PMID:27431039

  17. Design and validation of novel scattering foils for modulated electron radiation therapy

    NASA Astrophysics Data System (ADS)

    Connell, T.; Seuntjens, J.

    2014-05-01

    Modulated Electron Radiation Therapy (MERT) continues to be an area of interest to various groups, however, the scattering foils used in beam flattening have not been optimized for this modality. In this work, the feasibility of novel scattering foils specifically designed for MERT is investigated using Monte Carlo methods. Different designs based on foil material, shape and thickness were analyzed. It was shown that low atomic number materials such as aluminum were optimal, while shaped foils such as those employed in current dual foil designs were not necessary. Aluminum foil thickness between 0.36 mm and 1.50 mm were capable of sufficiently broadening beams with energies between 12 MeV and 20 MeV respectively, with beams of lower energies receiving sufficient scatter from the treatment head components and air scatter. Finally, custom foils were manufactured based upon previously simulated designs and were placed into the beamline of a 2100 EX accelerator, and showed excellent agreement between the simulated and measured PDDs and profiles. Custom foils achieved higher dose rates on the central axis compared to the clinical foils by factors of 5.4, 4.9 and 4.5 for 12 MeV, 16 MeV and 20 MeV, respectively.

  18. Personnel neutron dosimetry using electrochemically etched CR-39 foils

    SciTech Connect

    Hankins, D.E.; Homann, S.; Westermark, J.

    1986-09-17

    A personnel neutron dosimetry system has been developed based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This Cr-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. The dosimetry system employs an electrochemical etch procedure that be used to process large numbers of Cr-39 dosimeters. The etch procedure is suitable for operations where the number of personnel requires that many CR-39 dosimeters be processed. Experience shows that one full-time technician can etch and evaluate 2000 foils per month. The energy response to neutrons is fairly flat from about 80 keV to 3.5 MeV, but drops by about a factor of three in the 13 to 16 MeV range. The sensitivity of the dosimetry system is about 7 tracks/cm/sup 2//mrem, with a background equivalent to about 8 mrem for new CR-39 foils. The limit of sensitivity is approximately 10 mrem. The dosimeter has a significant variation in directional dependence, dropping to about 20% at 90/sup 0/. This dosimeter has been used for personnel neutron dosimetry at the Lawrence Livermore National Laboratory for more tha 18 months. 6 refs., 23 figs., 2 tabs.

  19. Fission fragment assisted reactor concept for space propulsion: Foil reactor

    NASA Technical Reports Server (NTRS)

    Wright, Steven A.

    1991-01-01

    The concept is to fabricate a reactor using thin films or foils of uranium, uranium oxide and then to coat them on substrates. These coatings would be made so thin as to allow the escaping fission fragments to directly heat a hydrogen propellant. The idea was studied of direct gas heating and direct gas pumping in a nuclear pumped laser program. Fission fragments were used to pump lasers. In this concept two substrates are placed opposite each other. The internal faces are coated with thin foil of uranium oxide. A few of the advantages of this technology are listed. In general, however, it is felt that if one look at all solid core nuclear thermal rockets or nuclear thermal propulsion methods, one is going to find that they all pretty much look the same. It is felt that this reactor has higher potential reliability. It has low structural operating temperatures, very short burn times, with graceful failure modes, and it has reduced potential for energetic accidents. Going to a design like this would take the NTP community part way to some of the very advanced engine designs, such as the gas core reactor, but with reduced risk because of the much lower temperatures.

  20. A simple method for the measurement of reflective foil emissivity

    NASA Astrophysics Data System (ADS)

    Ballico, M. J.; van der Ham, E. W. M.

    2013-09-01

    Reflective metal foil is widely used to reduce radiative heat transfer within the roof space of buildings. Such foils are typically mass-produced by vapor-deposition of a thin metallic coating onto a variety of substrates, ranging from plastic-coated reinforced paper to "bubble-wrap". Although the emissivity of such surfaces is almost negligible in the thermal infrared, typically less than 0.03, an insufficiently thick metal coating, or organic contamination of the surface, can significantly increase this value. To ensure that the quality of the installed insulation is satisfactory, Australian building code AS/NZS 4201.5:1994 requires a practical agreed method for measurement of the emissivity, and the standard ASTM-E408 is implied. Unfortunately this standard is not a "primary method" and requires the use of specified expensive apparatus and calibrated reference materials. At NMIA we have developed a simple primary technique, based on an apparatus to thermally modulate the sample and record the apparent modulation in infra-red radiance with commercially available radiation thermometers. The method achieves an absolute accuracy in the emissivity of approximately 0.004 (k=2). This paper theoretically analyses the equivalence between the thermal emissivity measured in this manner, the effective thermal emissivity in application, and the apparent emissivity measured in accordance with ASTM-E408.